Question: The sum of the present ages of Sujith and Leela is 47 years. Ten year ago, Sujith's age was 13 times the difference in their present ages. Find the Leela's present age?

A: 23 years
B: 24 years
C: 25 years
D: 26 years

Ans: B
Solution: Let present age of Sujith = x
present age of Leela = y
According to question,
x + y = 47
x - 10 = 13 | x - y | , where | | is modulus
either  x-10 = 13(x - y)         or,  x-10 = 13(y-x)
or     47-y-10=13(47-2y)            ;    37-y -10= 13(y- 47+y)
or     37 - y = 611 - 26y              ;    37 - y = 26y - 611
or     25y = 574                           ;   27y = 648
or y = 574/25                              ;    y = 24

So, y = 24
and x = 47-24 = 23

Hence Age of Leela = y = 24 Ans