Question

A shopkeeper sells two types of books national books and international books .He sells national books at Rs. 18 / book and incurs at loss of 10% whereas on selling the international books at Rs. 30 / book ,he gains 20 % .Find the ratio of the national and international books such that he can gain a profit of 25% by selling the combined books at 27.5/ book ?

Answer 1

Let the ratio of national to international books be $1:x$

Let the cost price of national book be $N$ and cost price of international book be $I$

Then According to question , $N\times \frac{9}{10}=18$

And , $I\times \frac{6}{5}=30$

Solving we get $N=20$ and $I=25$

Again According to question ($20\times 1+25\times x$)$\frac{5}{4}=27.5\times$ ($x+1$)

Solving we get $x=\frac{2}{3}$

So ratio of national books to international boks = $3:2$