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.
Choose the correct choice from the following.
A) 1 : 3 B) 5 : 2 C) 3 : 4 D) 2 : 5 E) None of these
Explanation:   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   ANSWER 5 : 2
<result>B</result>
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.