To gain 10% on selling the mixture of milk and water at the cost price of pure milk, the quantity of water to be mixed with 50 kg of pure milk is = ?

A. 2.5 kg

B. 5 kg

C. 7.5 kg

D. 10 kg

Answer: Option B

Solution(By Examveda Team)

Let cost price of 1 kg = Rs. 1
Cost price of 50 kg = Rs. 50
$$\eqalign{ & \Rightarrow {\text{Profit}} = \frac{{10}}{{100}} \times {\text{50}} \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = {\text{Rs}}{\text{. 5}} \cr & \therefore {\text{Quantity to added}} \cr & = \frac{5}{1} = {\text{5 kg}} \cr} $$