At present, the ratio of Arun's age to Deepak's age is 4:3. After 6 years, Arun will be 26 years old. What is Deepak's present age?

Problem restatementUse Arun's future age to back out his present age, then the 4:3 ratio to get Deepak's present age.

Given data

• Arun:Deepak = 4:3 now.
• Arun in 6 years = 26 ⇒ Arun now = 20.

Concept/ApproachIf 4 parts correspond to 20 years, then 1 part is 5 years; Deepak (3 parts) is 15.

Step-by-Step calculationArun now = 26 − 6 = 20Scale factor k: 4k = 20 ⇒ k = 5Deepak now = 3k = 15

Verification/AlternativeIn 6 years: Deepak = 21; ratio then 26:21 = 26:21 (not required), present ratio remains 4:3.

Common pitfallsAdding 6 to both ages first and then trying to compute the ratio back; simpler to get Arun now, then apply the current ratio.

Final Answer15 years