Question

Jon is thrice as old as Kavya. Five years ago his age was two times Kavya’s age. Find their present age.

(a) Kavya’s age = 15 years; Jon’s age = 5 years

(b) Kavya’s age = 5 years; Jon’s age = 15 years

(c) Kavya’s age = 5 years; Jon’s age = 5 years

(d) Kavya’s age = 15 years; Jon’s age = 15 years

The question was asked during an online interview.

Question is from Applications of Linear Equation (Create and Solve the Equations) topic in division Linear Equations in One Variable of Mathematics – Class 8

Answer 1

The correct answer is (b) Kavya’s age = 5 years; Jon’s age = 15 years

To elaborate: Let us consider Kavya’s age as x years.

Then Jon’s age would be 3x years.

Kavya’s age five years ago was (x – 5) years.

Jon’s age five years ago was (3x – 5) years.

It is given that Jon’s age five years ago was two times Kavya’s age.

Thus, (3x – 5) = 2 * (x – 5)

Or 3x -5 = 2x – 10

Or x = 5

∴ Jon’s age = 3x

∴ Jon’s age = 3 * 5

∴ Jon’s age = 15 years

∴ Kavya’s age = x

∴ Kavya’s age = 5 years.