Alligation or Mixture - General Aptitude

Q1:

The cost of Type 1 rice is Rs. 15 per kg and Type 2 rice is Rs. 20 per kg. If both Type 1 and Type 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

ANS:A - Rs. 18

Let the price of the mixed variety be Rs. x per kg. By rule of alligation, we have:

Cost of 1 kg of Type 1 rice Cost of 1 kg of Type 2 rice
Rs. 15 Mean Price
Rs. x
Rs. 20
(20 - x) (x - 15)
(20 - x) = 2
(x - 15) 3
60 - 3x = 2x - 30 5x = 90 x = 18.