Rajiv sells a book to Mohan at a profit of 9% and Mohan sells it to Gopal at a profit of 13%. If Gopal pays Rs 12,317 for it. Find the cost price for Rajiv.

Rs 10,000

Let the cost price of book be 100 units.

Rajiv sells it to Mohan at 9% profit,

Thus selling price = 109 units 

Mohan again sells it to Gopal at 13% profit,

Selling price for this transaction = $\frac{113}{100}$ x 109 = $\frac{113 \times 109}{100}$ units = 12317/100 units 

According to the question, this is equal to Rs 12,317

Using unitary method,

     1 unit  = Rs 100

Thus, 100 units = Rs 10,000

Cost price for Rajiv = Rs 10,000