Question

15 years ago , the mother's age was twice the daughter's age. If 3 years from now the sum of their ages will be 99, what is the difference between their present age ?

• A. 19 years
• B. 21 years
• C. 23 years
• D. 25 years

Answer 1

Answer:

B. 21 years

let 'm' be the mother's current age and 'd' be the daughter's current age. 15 years ago mother's age = m-15 15 years ago daughter's age = d-15 the mothers age was twice the daughter's age m-15=2(d-15) m-2d = -15 --(1) in 3 years mothers age will be m+3 and daughters will be d+3 the sum of their ages will be 99 (m+3)+(d+3)=99 m+d=93 --------(2) (2) - (1) = > (m+d)-(m-2d)=93-(-15) 3d=108 d=36 substitute d in ---(2) m+36=93 m=93-36 = 57 the difference between their present age is m-d = 57-36=21