In what ratio water must be added in milk costing ₹60 litre, so that resulting mixture would be worth ₹50 litre ?

1 : 5

The correct answer is option (2) : 1 : 5

Cost of water (c) = ₹0

Cost of milk (d) = ₹ 60 /litre

Cost of resulting mixture (m) = ₹ 50 /litre

So, $\frac{\text{quantity of water}}{\text{quantity of milk}}=\frac{10}{50}=\frac{1}{5}$

Hence, the required ratio is $1: 5$