Percentage

[Veronica]

Last Sunday a certain store copies of Newspaper A for $1 each and copies of Newspaper B for $1.25 each, and the store sold no other newspapers that day. If r percent of the store's revenues from newspaper sales was from Newspaper A and if p percent of the newspapers that the store sold were copies of newspaper A, which of the following expresses r in terms of p?
a. 100p/(125-p)
b. 150p/(250-p)
c. 300p/(375-p)
d. 400p/(500-p)
e. 500p/(625-p)

Thank u!

[euro]

Assume total no. of newspaper copies sold = 100

For Newspaper 'A', no. of copies sold = p% of 100 = p
For Newspaper 'A', revenue earned = p * $1 = $p


For Newspaper 'B', no. of copies sold = 100-p
For Newspaper 'B', revenue earned = (100-p) * $1.25 = $(125-1.25p)

Total Revenue from A & B = $p + $ 125 -1.25p = 125-0.25p

Revenue as % from newspaper A = r%

r = p/(125-0.25p) * 100

simplifying the above, we have r = 400p/(500-p)

The answer is D

[blaster]

i also get D