Question

A buys a chemical at Rs.240 per litre and adds 10 litres of water in it. To earn profit of 25%, he sells mixture at Rs. 250 per litre. Find the quantity of chemical he bought at Rs. 240.
1. 45 litres
2. 30 litres
3. 50 litres
4. 40 litres

Answer 1

Correct Answer - Option 3 : 50 litres

Calculation:

The cost price of a mixture of chemical and water = 250 × 100/125 = Rs. 200 

Cost price of water added = Rs. 0

Using rule of alligation,

Ratio of chemical to water = (200 - 0) ∶ (240 - 200) = 5 ∶ 1

Total quantity of mixture = 10 × 6/1 = 60 litres

∴ Quantity of chemical he bought at Rs. 240 = 5/6 × 60 = 50 litres

(Quantity of expensive item)/(Quantity of cheaper item) = (Mean Price - Price of cheaper item)/ (Price of expensive item - Mean price)