Find the ratio in which wheat of inferior quality (Rs.14/kg) be mixed with wheat of superior quality (Rs.28/kg) so that the shopkeeper gains Rs.2 by selling the resulting mixture at Rs.20/kg.
Answer: B
Let the resulting mixture be 1 kg, and x kg be the amount of wheat of inferior quality.
Therefore, (1-x)kg is the amount of wheat of superior quality.
As the shopkeeper gains Rs.2, the cost of the mixture is Rs.18
14*x + 28*(1-x) = 18
14x - 28x + 28 = 18
14x = 10
x = 5/7
(1 – x) = 2/7
x : (1-x) = 5/7 : 2/7
= 5 : 2