A person purchases 40 items at 10 Rs. each. He sells a part of them at 25% profit and the remaining at 10% loss. The net profit is 4% in this transaction. The no. of items he sold at profit is?

16

At 4% profit

SP = 400 × \(\frac{104}{100}\)% = 416

Let us suppose x items were sold at 25% profit

(40 -x) sold at 10% loss

{x × \(\frac{5}{4}\) x 10} + {(40 - x) × \(\frac{9}{10}\) x 10} = 416

\(\frac{5}{4}\)x + 36 - \(\frac{9}{10}\) x = 41.6

7x = 112

x = 16