Question

A shopkeeper sells a book for $Rs.36$ and gains $\frac{5}{7}$ of what it costs him. Find the cost price of the book.

• A. $31$
• B. $25$
• C. $21$
• D. $24$

Answer 1

The correct option is C $21$

Selling price = cost price + profit

Let cost price $=x$

The profit $=\frac{5x}{7}$

So

selling price $=36=x+\frac{5}{7}x=\frac{12x}{7}$
$x=3\times 7=21=$ Cost price