The average age of father and his son is 22 years. The ratio of their ages is 10 : 1 respectively. What is the age of the son?

Adam who is 20 years old is 4 times as old as Mary. What will be Mary’s age when Adam is twice as old as her?

If -4$1 = 4, 7$-7 = 49 and 3$1 = -3, then find the value of -8$-5 = ?

If "P" denotes "multiplied by", "R" denotes "subtracted from", "S" denotes "added to" and "Q" denotes "divided by", then which of the following equation is true?

Study the following information carefully and answer the questions given below:
There are six persons of different weights. Three persons are heavier than Rohan. Two person’s weight is in between Sohan and Geeta. Rajesh is heavier than Rakesh but lighter than Ram. Neither Rakesh nor Geeta is lightest person. Weight of 2nd heaviest person is 66kg. Weight of all persons are in whole numbers. What is the weight of Sohan?

The following equation is incorrect. Which two signs should be interchanged to correct the equation?
12 + 10 - 28 ÷ 7 x 4 = 48

If P means -, Q means +, R means x and  S means ÷ then what is the value of  8 R6S3Q5P9 

The sum of the ages of a father and his son is 56 years. After 4 years, the father's age will be 3 times his son's age. Their ages are respectively.