Lets assume, total sold = 100 (because easy to calculate)
Last Sunday, News Paper - A sales = x then News-paper-B sales = (100-x)
they have given each price of NP-A & NP-B, then
Revenue from NP-A = x (1$) = $x
Revenue from NP-B = (100-x)($1.25) = $125-1.25x
Total Revenue = Store's Revenue = NP-A revenue + NP-B revenue = x + 125 - 1.25x = $(125 - 0.25x)
Given p% of total papers sold was NP-A. We can write as,
p% of total papers(100) = No.of NP-A sold (take values from the above statements)
(p/100) * (100) = x
then p = x
Given, r% of Store's Revenue was only from NP-A. we can write as,
r% of Store's Revenue(Total Revenue) = Revenue from NP-A
(r/100) * (125 - 0.25x) = x(1$)
r = (100x)/ (125-0.25x)
multiply & divide by 100/100
r = (100x)(100)/(12500 - 25x)
Cancel with 25 on both numerator & denominator on the Right-hand side.
r = (400x)/(500-x)
From above statement, substitute x=p;
r = (400p)/(500-p). So, CORRECT ANSWER is D.
HTH, GOOD LUCK,
Thanks,
Rajesh,
Loves GMAT....!!!
