Question

Last Sunday a certain store sold copies of Newspaper A for $1 and Newspaper B for 1.25. If r percent of the stores revenue came from newspaper sales of Paper A and if p percent of the newspapers sold that day were A, which of the following expresses r in terms of p?
100p/125-p
150p/250-p
300p/375-p
400p/500-p
500p/625-p

Answer 1

Answer:

Option 400p/500-p

Step-by-step explanation:

Let the number of newspaper A sold be 'x'

and the number of newspaper A sold be 'y'

Therefore,

Total revenue = $1x + $1.25y

Total newspapers sold = x + y

Therefore,

according to the question

r = $\frac{x}{x + 1.25y}\times100$ ..........(1)

and,

p =  $\frac{x}{x + y}\times100$

or

(x + y)p = 100x

or

y = $\frac{x}{p}\times100-x$

or

y = $\frac{x(100-p)}{p}$

substituting y in 1

r = $\frac{x}{x + 1.25(\frac{x(100-p)}{p})}\times100$

or

r = $\frac{100p}{p+125-1.25p}$

or

r = $\frac{100p}{125-0.25p}$

multiply and divide the RHS with 4

we get

r = (400p)÷(500-p)

hence,

Option 400p/500-p