In an age ratio relationship, Ravi's age is twice Prakash's age and three times Kumar's age. If Prakash is 24 years old at present, what will be Kumar's age after 4 years?

Introduction:
This is a standard “multiples of ages” question. When one person's age is given as a multiple of another person's age, you can convert these relations into equations. Since Prakash's age is known, we can directly compute Ravi's age, and then use Ravi's age to compute Kumar's present age. Finally, we add 4 years to answer the “after 4 years” requirement.

Given Data / Assumptions:

• Prakash's present age = 24 years
• Ravi's age = 2 * (Prakash's age)
• Ravi's age = 3 * (Kumar's age)
• We need Kumar's age after 4 years

Concept / Approach:
Use the chain: Prakash -> Ravi -> Kumar. Convert multiples into direct arithmetic and then shift time by adding 4 years to Kumar's present age.

Step-by-Step Solution:
Ravi's present age = 2 * 24 = 48Since Ravi = 3 * Kumar, Kumar's present age = 48 / 3 = 16Kumar's age after 4 years = 16 + 4 = 20

Verification / Alternative check:
Check the multiples: If Kumar is 16, then 3 * 16 = 48 which equals Ravi's age. Also Ravi is twice Prakash: 2 * 24 = 48. Both relations hold, so the base ages are correct.

Why Other Options Are Wrong:
16 years: this is Kumar's present age, not after 4 years.18 years: implies adding only 2 years instead of 4.24 years: confuses Kumar's age with Prakash's age.22 years: would require Kumar present to be 18, which breaks Ravi = 3 * Kumar.

Common Pitfalls:
Forgetting to add 4 years at the end.Dividing by the wrong multiple (using 2 instead of 3).Mixing up which person is a multiple of whom.

Final Answer:
20 years