The sum of the present ages of Varun and Kapil is 42 yr. The ratio of their ages after 5 yr will be 15 : 11. What is the present age of Kapil?

Let the present age of Varun be M and present age of Kapil be N.
According to the questions,
M + N = 42 ...(i)
Again, according to the question, After 5 yr,
(M + 5)/(N + 5) = 15/11
⇒ 11M + 55 = 15N + 75
⇒ 11M - 15N = 20 ...(ii)
On solving Eqs. (i) and (ii),
⇒ N = 17 yr
Hence, present age of Kapil = 17 yr