Question

A 52 year-old father has a son and a daughter. The son is twice as old as the daughter. In 4 years the sum of all their ages will be 100. How old are the two siblings now? (RSM problem)

Answer 1

Answer: son 24 daughter 12

100= total years of age of all ppl in 4years but we want their age now

100=(52+4)+(2x+4)+(x+4)

3x=36

x=12

So daughter is 12 and son is 2x or 24

Any questions on how to set this up or how to arrive at the answer, please feel free to ask. Thanks!

Answer 2

Answer:The age of daughter is 12 years and age of son is 24 years

Explanation:

Given :

Present age of father = 52 years

Let the present age of daughter be x

So according to the question son's age is twice that of daughter's

So present age of son =2x

Now after 4 years the sum of their ages = 100

i.e. x+4 + 2x+4 + 52 +4 =100

3x+ 64 = 100

Subtracting both sides by 64 we get

3x + 64 - 64=100 -64

3x = 36

Dividing LHS and RHS by 3 we get

x=12

i.e. Present age of daughter = x = 12 years

Present age of son = 2x = 2× 12= 24 years