Tom will be 25 years old in n years' time. If he is 5 years younger than Bade, find Bade's present age.

Analyze the question

We are told Tom will be 25 in n years' time, and Tom is 5 years younger than Bade. We need Bade's present age in terms of n.

Concept

"Will be 25 in n years" means: present age + n = 25. Being "5 years younger" means Bade's age = Tom's age + 5.

Solution

1. Tom's present age: T + n = 25, so T = 25 − n
2. Bade is 5 years older than Tom: B = T + 5 = (25 − n) + 5 = 30 − n

Bade's present age = (30 − n) years

Check: Let n = 5. Tom is 20 now and will be 25 in 5 years. Bade is 25 now. The formula gives 30 − 5 = 25. ✓

Tip: For "in n years' time" questions, find the present age first by subtracting n from the future age. Then apply the "older/younger" difference. Substituting a simple number for n is a fast way to verify your answer in the exam.