Question & Answer
QUESTION

Ten years ago a father was six times as old as his daughter. After 10 years, he will be twice as old as his daughter. Determine the sum of their present ages.

ANSWER Verified Verified
Hint:
Tip #1: In case you get confused in age questions, make a table.

Tip#2: When you get the age of one person a direct multiple of another, it is generally useful to start assuming variables in that time period. For example, in this question, I have taken daughter's age 10 years back as 'd'. Other numbers are as follows:



10 years ago

      Today

       10 years later

Daughter       

d

       d+10

       d+20

Father

6d

      6d+10

       6d+20


Now, try to solve this yourself before looking at the calculations.


Complete step-by-step answer:
As given in the question, 10 years from now the father is twice the daughter's age.
Hence, 
6d+20 = 2(d+20)

Means, 4d = 20 or d = 5.

The sum of their current ages = (d+10) + (6d+10) = 7d+20 = 55.

So, the answer is 55 years.

Note:  
Common mistake in such questions is to write down the age of the father or the daughter as the final answer. Read the question carefully to avoid such mistakes.