1)

The cost of type 1 rice is Rs.15 per kg and type 2 rice is Rs.20 per kg.If both type1 and 2 are mixed in the ratio of 2 : 3, then the price per kg of the mixed variety of rice is 


A) Rs.18

B) Rs.18.50

C) Rs.19

D) Rs.19.50

Answer:

Option A

Explanation:

Let the price of mixed variety be =Rs.x

By the rule of alligation 

C.P of 1 kg of type 1 rice=Rs.15 ie x-15 to mean price Rs.x

C.P of 1 kg of type 2 rice=Rs.20 ie 20-x to mean price Rs.x

Given $\frac{20-x}{x-15}=\frac{2}{3}$

$\Rightarrow 60-3x=2x-30,x=18$

Price of the mixture is Rs. 18 per kg.