The difference between the ages of mother and son was 21 when mother's age was 43. If father is elder by 3 years to mother, what will be the difference between the ages of son and father when father attains 50 years?
A shop keeper purchased 15 kg of sugar and 20 kg of wheat at Rs. 50 and Rs. 75 per kg respectively. On selling them, he gained 10% on sugar and 20% on wheat. What was the total sale vale?