Michelle purchased 25 audio files in january . in February she purchased 40 audio files. what is the percent increase ?

QUESTION POSTED AT 14/12/2019 - 05:03 PM

Answered by admin AT 14/12/2019 - 05:03 PM

So, first: what is the absolute increase?

The absolute increase is: 40-25=15. So the absolute increase is 15.

Now, 15 is what percentage of 25?

we count this as follows:

 \frac{15}{25}= \frac{3}{5} =0.8

0.8*100%=80%.

So percent increase is 80%.
Post your answer

Related questions

Tanisha is graphing the function f(x) = 25(3/5)^x. She begins by plotting the point (1, 15). Which could be the next point she plots on the graph? (2, 9) (2, –10) (2, 14 2/5) (2, 5)

The answer is (2,9).

This is because we can increment X by 1, giving us X=2. We can then do:
f(2)=25•(3/5)^2
Which equals:
f(2)=25•(3^2/5^2) because (a/b)^c = a^c/b^c.

We can then calculate the fraction in a simplified form:
f(2)=25•(9/25)=225/25
which fully simplified gives us
f(2)=9/1=9

ANSWERED AT 18/01/2020 - 07:20 AM


QUESTION POSTED AT 18/01/2020 - 07:20 AM

According to the Rational Roots Theorem, which statement about f(x) = 25x^7 – x^6 – 5x^4 + x – 49 is true? Any rational root of f(x) is a multiple of –49 divided by a multiple of 25. Any rational root of f(x) is a multiple of 25 divided by a multiple of –49. Any rational root of f(x) is a factor of –49 divided by a factor of 25. Any rational root of f(x) is a factor of 25 divided by a factor of –49.

Answer:

Any rational root of f(x) is a factor of -49 divided by a factor of 25.

Step-by-step explanation:

The Rational Root Theorems states that :

If the polynomial P(x)= a _nx^n +{a_{n-1}x}^{n-1}+............{a_{2}x}^{2}+{a_{1}x}^{1}+a_0 has any rational roots, then they must be in the form of

\pm \frac{factors of a_0}{factors of a_n}

Consider the polynomial

f(x)=25x^7-x^6-5x^4+x-49

in this case, we have a_0=-49 and a_n=25

Any Rational root of f(x) is a factor of  a_0=-49 divided by a factor of a_n=25


ANSWERED AT 18/01/2020 - 07:18 AM


QUESTION POSTED AT 18/01/2020 - 07:18 AM

What value of a makes the equation true 18/60=12/a a 30 b 4 c 20 d 40

The answer is d 40
by applying the cross product

ANSWERED AT 18/01/2020 - 07:16 AM


QUESTION POSTED AT 18/01/2020 - 07:16 AM

Which products result in a perfect square trinomial? Check all that apply. A=(–x + 9)(–x – 9) B=(xy + x)(xy + x) C=(2x – 3)(–3 + 2x) D=(16 – x2)(x2 – 16) E=(4y2 + 25)(25 + 4y2)

The correct answers are:

B=(xy + x)(xy + x) ; C=(2x – 3)(–3 + 2x) ; and E=(4y² + 25)(25 + 4y²)

Explanation:

In order to have a perfect square trinomial, we must multiply two binomials that are exactly the same.  For (xy+x)(xy+x), are multiplying two identical binomials.

For (2x-3)(-3+2x), we are multiplying two binomials that are the same but written in a different order.  The same is true of (4y² + 25)(25 + 4y²).

ANSWERED AT 18/01/2020 - 07:11 AM


QUESTION POSTED AT 18/01/2020 - 07:11 AM

2.)The resale value of a textbook decreases by 25% with each previous owner. A new textbook is sold for $85. Which function represents the resale value of the textbook after x owners? f(x) = 85(1 – 0.25)^x f(x) = 85(1 + 0.25)^x f(x) = 85(0.25)^x f(x) = (85 – 0.25)^x

Since they value of the book is decaying, we are going to adapt the standard exponential decay function to solve this.

Exponential decay function: f(x)=a(1-b)^x

where

f(x) is the final amount remaining after x years of decay

a is the initial amount

b is the decay rate in decimal form

x is the time in years

Now, let's adapt the equation to suit our needs

Since the value of the book is decaying with the number of owners and not with time, we are going to let  x be the number of previous owners instead of time. So now  f(x) will represent the final cost of the book after  x owners, and  a will be the initial cost of the book.

Exponential decay function: f(x)=a(1-b)^x

where

f(x) is the final cost of the book after x owners

a is the initial cost of the book

b is the decay rate in decimal form

x is the number of previous owners

Now, we know from our problem that the initial cost of the book is $85, so  a=85 . We also know that the resale value of a textbook decreases by 25% with each previous owner; to convert the decay rate (25%) to decimal form, we are going to divide it by 100%:

 b=\frac{25}{100}

 b=0.25

We have everything we need so let's replace the values in our exponential decay equation:

f(x)=a(1-b)^x

f(x)=85(1-0.25)^x

We can conclude that the correct answer is A) f(x) = 85(1 – 0.25)^x

ANSWERED AT 18/01/2020 - 07:07 AM


QUESTION POSTED AT 18/01/2020 - 07:07 AM

Which quotient will be negative? 36 ÷ (-4) 40 ÷ 8 -42 ÷ (-7) 12 ÷ 4

I think the answer will be like this:
36÷(-4)= -9
40÷8=5
-42÷(-7)=6
12÷4=3
so the answer is 36÷(-4)

ANSWERED AT 18/01/2020 - 07:05 AM


QUESTION POSTED AT 18/01/2020 - 07:05 AM

Mira picked two numbers from a bowl. The difference of the two numbers was 4, and the sum of one-half of each number was 18. The system that represents Mira’s numbers is below. x – y = 4 x + y = 18 Which two numbers did Mira pick? (10, 8) (18, 4) (20, 16) (40, 32)

Let

x------> the first number

y-----> the second number

Assume x> y

we know that

x-y=4 ----> equation A

\frac{x}{2}+ \frac{y}{2}=18

Multiply by 2 both sides

x+y=36-----> equation B

Adds equation A and equation B

x-y=4 \\x+y=36\\------- \\ x+x=4+36\\ 2x=40\\ x=20

Find the value of y

20-y=4

y=20-4=16

therefore

the answer is the option

(20,16)

ANSWERED AT 18/01/2020 - 07:05 AM


QUESTION POSTED AT 18/01/2020 - 07:05 AM

The function f(t) = 25 sin (pi over 2t) + 10 models the temperature of a periodic chemical reaction where t represents time in hours. What are the maximum and minimum temperatures of the reaction, and how long does the entire cycle take? Maximum: 35°; minimum: −15°; period: 4 hours<--- my answer Maximum: 25°; minimum: 10°; period: pi over 2 hours Maximum: 100°; minimum: −15°; period: pi over 2 hours Maximum: 35°; minimum: 35°; period: 8 hours

Answer:

The correct answer is:

                   Maximum: 35°; minimum: −15°; period: 4 hours

Step-by-step explanation:

We are given a function f(t) which represent the temperature of a periodic chemical equation as:

      f(t)=25\sin (\dfrac{\pi}{2}t)+10

Hence, the maximum value of the function is attained when Sine function is maximum and the minimum value is attained when the sine function attains the minimum value.

We know that the Maximum value of sine function=1

and Minimum value of Sine function is: -1

when Sine function=1

we have: f(t)=25+10=35°

Hence, Maximum value of function= 35°

Also when Sine function= -1

We have: f(t)= -25+10= -15°

Minimum value of function= -15°

Also, we know that period of sine function of the type:

a\sin (bt)+c is given by:

Period=\dfrac{2\pi}{b}

Here we have:

b=\dfrac{\pi}{2}

Hence,  Period=\dfrac{2\pi}{\dfrac{\pi}{2}}\\\\\\Period=4

Hence,  Period=4

ANSWERED AT 18/01/2020 - 07:03 AM


QUESTION POSTED AT 18/01/2020 - 07:03 AM

The outlier, 78, is removed from the data set shown. 23, 23, 25, 27, 34, 34, 35, 41, 45, 45, 78 How does this affect the range? A.) The range is decreased by 4. B.) The range is decreased by 16. C.) The range is decreased by 22. D.) The range is decreased by 33.

An outlier of a set of data is a data value that is too small or too large compared to other values in the set of data. Range of a set of data is the difference between the largest data value and the smallest data valu in the set of data. Range of 23, 23, 25, 27, 34, 34, 35, 41, 45, 45, 78 is 78 - 23 = 55 When the outlier 78 is removed, the range of the data set 23, 23, 25, 27, 34, 34, 35, 41, 45, 45 is 45 - 23 = 22 Thus, when the outlier 78 is removed, the range of the data set decreases by 55 - 22 = 33. Therefore, the correct answer to the question "The outlier, 78, is removed from the data set shown. 23, 23, 25, 27, 34, 34, 35, 41, 45, 45, 78 How does this affect the range?" is "The range is decreased by 33." (option D).

ANSWERED AT 18/01/2020 - 07:01 AM


QUESTION POSTED AT 18/01/2020 - 07:01 AM

Which of the following is not a disadvantage of using credit instead of cash? a. Credit cards increase the likelihood of impulse buying. b. Credit cards can be used to increase your credit score. c. Credit cards generally come with interest and other fees that cash does not. d. Credit cards require a good credit rating and responsible credit maintenance.

Answer: b. Credit cards can be used to increase our credit score.


Step-by-step explanation: Option (a) which tells tells that credit cards increase the likelihood of impulse buying is a disadvantage, since it increases our monthly expenditure which may or may not fall in our budget. Secondly, according to option (c) credit cards come with interest fees and all which is also a kind of disadvantage and option (d) is also a disadvantage as credit cards requires a good maintenance. The only advantage of credit cards amongst the given is option (b) because credit cards are helpful in increasing our credit scores.

Thus, the correct option is (b).


ANSWERED AT 18/01/2020 - 06:59 AM


QUESTION POSTED AT 18/01/2020 - 06:59 AM

The table gives sales data for a stationery store in any given two weeks. It lists the probability of the number of items purchased in a single transaction and the average amount spent per transaction. Items Purchased in a Single Transaction Probability Average Amount Spent 2 0.35 $12 3 0.17 $20 4 0.33 $28 5 or more 0.15 $36 Based on the data provided, transactions with items are likely to bring in the most income during the next two-week transaction period.

From the given data:

Number of items | Probability of being purchased | Average amount spent
--------------------------------------------------------------------------------------------------
            2              |                     0.35                      |            $12
            3              |                     0.17                      |            $20
            4              |                     0.33                      |            $28
       5 or more      |                     0.15                      |            $36

In a sample space of 100 items being purchased, in a day:

For 2 items: 35 (12) = 420
For 3 items: 17 (20) = 340
For 4 items: 33 (28) = 924
For 5 or more items: 15 (36) = 540

If this sample trend would go on the for the next two weeks, then the transaction with 4 items would most likely bring in the most income during the said transaction period.

ANSWERED AT 18/01/2020 - 06:55 AM


QUESTION POSTED AT 18/01/2020 - 06:55 AM

Emma earns $6 each time she mows the lawn and $8 per hour for babysitting. She is saving up to buy a new pair of jeans that cost $48. If she mows the lawn x times and babysits for y hours, which graph shows the amount of work she needs to complete to earn at least enough to purchase the new jeans?

To graph this we find the x- and y-intercepts. The x-intercept would be at 8 and the y-intercept would be at 6.

Explanation:
The equation is 6x+8y=48. An x-intercept is the point where the data crosses the x-axis. All points on this line will have a y-coordinate of 0, so we replace y with 0 and solve:
6x+8(0)=48
6x=48.

Divide both sides by 6:
6x/6=48/6
x=8.
We go to 8 on the x-axis and plot the point.

A y-intercept is the point where the data crosses the y-axis. All points on this line will have an x-coordinate of 9, so we replace x with 0 and solve: 6(0)+8y=48
0+8y=48
8y=48.

Divide both sides by 8:
8y/8 = 48/8
y=6.

We go up to 6 on the y-axis and plot the point. We then draw a line through these two points.

ANSWERED AT 18/01/2020 - 06:51 AM


QUESTION POSTED AT 18/01/2020 - 06:51 AM

Suppose you are determining the growth rate of two species of plants. Species A is 25 cm tall and grows 3 cm per month. Species B is 10 cm tall and grows 8 cm per month. Which system of equations models the height of each species H(m) as a function of months m.

Let
HA(m) = the height of species A as a function of months m
HB(m) = the height of species B as  a function of months m

Assuming that the growth rate of the plants is a linear relationship all throughout the growth stages, we have:
HA(m) = 25 + 3m
and
HB(m) = 10 + 8m

ANSWERED AT 18/01/2020 - 06:45 AM


QUESTION POSTED AT 18/01/2020 - 06:45 AM

Which shows a difference of squares? 10y2 – 4x2 16y2 – x2 8x2 – 40x + 25 64x2 – 48x + 9

The second choice 16y2 - x2 shows a difference of squares.
factoring the second choice results to (4y-x)(4y+x) which results to the difference between 4y and x. 

the first choice also shows a difference in the square however sqrt10 is not a perfect radical. 

ANSWERED AT 18/01/2020 - 06:43 AM


QUESTION POSTED AT 18/01/2020 - 06:43 AM

Which of the following is not a disadvantage of using cash instead of credit? a. Using cash will not help you improve your credit rating. b. Using cash can be awkward when making large purchases. c. Using cash generally requires trips to the bank or ATM to keep cash on hand. d. Using cash can make it easier to over-spend since you know exactly how much you have.

The correct answer is:

D) Using cash can make it easier to over-spend since you know exactly how much you have.

Explanation:

Knowing exactly how much you have on hand will actually help you avoid over-spending.

When using cash, you are aware of exactly how much money you have. With a credit card, this may not be the case; this makes it easier with a credit card to spend more money than you should for your budget. With cash it's easier to avoid this problem.

ANSWERED AT 18/01/2020 - 06:40 AM


QUESTION POSTED AT 18/01/2020 - 06:40 AM

Melinda and Paul shovel driveways and sidewalks in the winter as a way to earn extra money. Together they shoveled 450 square feet of sidewalk in 30 minutes. Then Melinda shoveled for 20 minutes while Paul shoveled for 25 minutes to complete 345 square feet of driveway. 30x + 30y = 450 20x + 25y = 345 How much more can Paul shovel in 1 minute than Melinda? 3 square feet per minute 6 square feet per minute 9 square feet per minute 15 square feet per minute

Answer: Hello mate!

we have the system of equations

30x + 30y = 450

20x + 25y = 345

where x is the number of square feet of snow that Melinda shovels in one minute, and y is the number of square feet of snow that Paul shovels in one minute.

Let's solve the system of equations, first, isolate one of the therms in the first equation, for example, x.

30x+30y = 450

x + y = 450/30 = 15

x = 15 - y

now we can replace it in the second equation and solve it for y.

20x + 25y = 345

20(15 - y) + 25y = 345

300 - 20y + 25y = 345

5y = 45

y = 45/5 = 9

Paul can shovel 9 square feets of snow in one minute, now replace it in the first equation and solve it for x.

x + y = 450/30 = 15

x + 9 = 15

x = 15 - 9 = 6

so melinda sholves 6 square feet of snow in one minute.

The question is:

How much more can Paul shovel in 1 minute than Melinda?

We need to see the difference y - x = 9 - 6 = 3

this means that paul shovels 3 more square feet per minute than Melinda.

ANSWERED AT 18/01/2020 - 06:36 AM


QUESTION POSTED AT 18/01/2020 - 06:36 AM

Tom earned £173 last week and he worked for 25 hours. how much does he earn?

TOm earned 173 dollars Last week working for 25 hours.
Now, if you're asking about his earnings, it's 173 dollars.
But if you're asking about his hourly rate.Let's find out:
=> 173 / 25 = 6.92 dollars per hour.

ANSWERED AT 18/01/2020 - 06:35 AM


QUESTION POSTED AT 18/01/2020 - 06:35 AM

Use the following compound interest formula to complete the problem. Sandra has two credit cards, P and Q. Card P has a balance of $726.19 and an interest rate of 10.19%, compounded semiannually. Card Q has a balance of $855.20 and an interest rate of 8.63%, compounded monthly. Assuming that Sandra makes no purchases and no payments with either card, after four years, which card’s balance will have increased by more, and how much greater will that increase be? a. Card Q’s balance increased by $7.22 more than Card P’s balance. b. Card Q’s balance increased by $6.69 more than Card P’s balance. c. Card P’s balance increased by $3.43 more than Card Q’s balance. d. Card P’s balance increased by $0.80 more than Card Q’s balance.

Card P's balance increased by $3.43 more than Card Q's balance. The accumulated total on Card P over the 4 years is $1080.70 and the accumulated total of Card Q is $1,206.28. Based on the principal outlay however, Card P would have netted a higher interest over Card Q when the principal is subtracted from the accumulated value. (For eg. Card P accumulated value $1080.70 less Principal $726.19 equals $354.51).The interests over the 4 years period would be $354.51 and $351.08 respectively, hence Card P having an increase in balance of $3.43 over Card Q.

ANSWERED AT 18/01/2020 - 06:34 AM


QUESTION POSTED AT 18/01/2020 - 06:34 AM

The table below shows the number of years after the year 2000 and the percentage of people of a country owning homes: Number of years after 2000 (x) 2 4 5 1 3 7 6 Percentage of people owning homes (y) 24% 32% 36% 20% 28% 44% 40% What is the correlation coefficient for the data, and what does it represent? (A) 0; it represents no correlation between x and y (B)1; it represents a perfectly linear positive correlation between x and y (C)1; it represents a perfectly linear negative correlation between x and y (D)−1; it represents a perfectly linear negative correlation between x and y

Answer:

The correlation coefficient is:

(B)  1; it represents a perfectly linear positive correlation between x and y

Step-by-step explanation:

We are given a table as:

x    1        2         3       4           5       6          7

y   20%   24%   28%  32%    36%     40%    44%

where x represent The number of years after 2000.

and y represents Percentage of people owning homes.

Clearly from the table we could see that the percentage of homes keeps on increasing as the number of years increases.

Hence the relationship is a strong Linear positive relationship.

The best fit line for the given data is this:

y = 0.04 x + 0.16

Hence, the correlation coefficient is: 1.

(B)  1; it represents a perfectly linear positive correlation between x and y

ANSWERED AT 18/01/2020 - 06:32 AM


QUESTION POSTED AT 18/01/2020 - 06:32 AM

The data represent the ages of people working at a store. 20, 30, 22, 29, 24, 27, 33, 25, 21, 19, 23 What is the first quartile of these ages? A. 19 B. 29 C. 21 D. 20

First, arrange the data from lowest to highest
19, 20, 21, 22, 23, 24, 25, 27, 29, 30, 33

Next, find the media or the middle data.
The median is 24.
19, 20, 21, 22, 23, 24 (median), 25, 27, 29, 30, 33

Lastly, look at the data below the median and find the middle of those data. If it's between two numbers, choose the lower number. That's the first quartile.
The first quartile is 21.
19, 20, 21(Q1), 22, 23, 24 (median), 25, 27, 29, 30, 33

ANSWERED AT 18/01/2020 - 06:32 AM


QUESTION POSTED AT 18/01/2020 - 06:32 AM

Last semester, 150 out of the 800 students at Jungle Junior High made the Honor Roll. What percent of the students made the Honor Roll?

To find out the percentage of made of honor roll, the actual success amount should be divided by whole number then multiply with 100.

(150 / 800) * 100
18.75 percentage

ANSWERED AT 18/01/2020 - 06:30 AM


QUESTION POSTED AT 18/01/2020 - 06:30 AM

On a math test, Miranda got 17 out of 20 problems correct. What percent of the problems were correct?

If we want to calculate the percentage of the correct answer, we can use this formula.

(17/20) * 100
85 percentage

ANSWERED AT 18/01/2020 - 06:30 AM


QUESTION POSTED AT 18/01/2020 - 06:30 AM

Percent of decrease of 120 to 52

Percent decrease=(decrease)/(original) converted to percent

change=120 to 52
120-52=68
change or decrease=68
original=120
68/120=0.5666666=56.6666%
about 57%

ANSWERED AT 18/01/2020 - 06:29 AM


QUESTION POSTED AT 18/01/2020 - 06:29 AM

Percent of decrease of 120 to 52

   
\displaystyle  \\ &#10;p =  \frac{120-52}{120}\times 100 =   \frac{68}{120}\times 100 =  0,5(6) \times 100 = \boxed{56 \% }



ANSWERED AT 18/01/2020 - 06:29 AM


QUESTION POSTED AT 18/01/2020 - 06:29 AM

24 songs to 78 songs, find the percent in change, I had tried to work it out and i got 30% but its wrong

78 * ( x/100) = 24 78 * x = 24 * 100 78 * x = 2400 X = 2400/28 X = 400/13 X = 30.77% The percent is 30.77

ANSWERED AT 18/01/2020 - 06:24 AM


QUESTION POSTED AT 18/01/2020 - 06:24 AM