Venkat sells 80 kg of onions. He sells some of them at a 5% loss (they were going soft) and the rest at a 15% profit. Overall he gains 9%. How many kg did he sell at a loss?

Explanation

1. 01

   Write the loss as −5%, and apply alligation to −5% and +15% around +9%.

2. 02

   Loss part : profit part = $(15 - 9)$ : $(9 - (-5)) = 6 : 14 = 3 : 7$.

3. 03

   Quantity sold at a loss = $\frac{3}{10} \times 80 = 24$ kg.