A man mixes 5 litres of milk costing Rs 60 per litre with 6 litres of milk costing Rs 58 per litre. How many litres of water should be added to make the cost of the mixture Rs 48 per litre?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 2.5
Adding free water does not change the total cost; it only increases the volume. So the total cost divided by Rs 48 gives the volume the mixture must reach.
Total cost \(=5\times60+6\times58=300+348=\) Rs 648
Volume needed at Rs 48 per litre \(\displaystyle =\frac{648}{48}=13.5\) litres
Milk already present \(=5+6=11\) litres
Water to add \(=13.5-11=2.5\) litres
2.5 litres of water must be added.