The average of present ages of 'Anna', 'Bob', and

Solution

ATQ, Sum of the present ages of 'Anna', 'Bob', and 'Charlie' = 20 x 3 = 60 years. Sum of the present ages of 'Bob', 'Charlie', and 'David' = (15 x 3) + (3 x 3) = 54 years. Difference between the present ages of 'Anna' and 'David' = 60 - 54 = 6 years. Let the present ages of 'Anna' and 'David' be 'a' years and 'd' years, respectively. a - d = 6 -----------(i) Sum of present ages 'A' and 'D' = 40 years. a + d = 40 ---------(ii) Adding equations (i) and (ii), we get: 2a = 46 Or, 'a' = 46 / 2 = 23 So, the age of 'Anna' five years ago from now = a - 5 = 23 - 5 = 18 years.