Question

By selling 12 marbles for a rupee, a shopkeeper loses 20% . In order to gain 20% in the transaction , he should sell the marbles at the rate of how many marbles for a rupee?

Answer 1

Let the cost price of one marble be $C$

According to question $\frac{4}{5}C$ $=$ $\frac{1}{12}$

To gain 20% S.P. should be $\frac{6}{5}C$ $=$ $\frac{1}{8}$

So he should sell $8$ marbles for a rupee .