Question

A merchant has 120 kg of rice. he sells a pact of it at a profit of 10% and the rest at a profit of 25%. he gains 15% on the whole. quantity of rice he sold at 25% gain is?

Answer 1

Let the required part be x kg.
Then the rest of mass is 100-x kg.
By the condition of the question,
(x*107/100) + ((100-x)*117/100) = (110*100/100).
Multiplying the equation by 100,
107x + 11700 - 117x = 11000.
=> 10x = 700, or,
x = 70 kg.