Expression for present age from a past value: Rahul is 8 years younger than Ritu at present. If Ritu’s age was x three years ago, which expression represents Rahul’s present age?

Difficulty: Easy

Correct Answer: x - 5

Explanation:

Introduction / Context:We must convert a past value into a present value and then incorporate a fixed difference. Ritu’s present age is derived from “x three years ago,” and Rahul’s is 8 less than that.

Given Data / Assumptions:

  • Ritu 3 years ago = x
  • Rahul is 8 years less than Ritu now

Concept / Approach:Ritu now = x + 3. Therefore Rahul now = (x + 3) − 8 = x − 5. Choose the expression that matches x − 5 exactly.

Step-by-Step Solution:

Ritu now = x + 3Rahul now = (x + 3) − 8 = x − 5

Verification / Alternative check:Plug a sample x (e.g., x = 20) to confirm the relationship is preserved correctly through time shifting and difference subtraction.

Why Other Options Are Wrong:x + 3 is Ritu now, not Rahul; x − 3 + 8 simplifies to x + 5, and x + 3 + 8 = x + 11—both contradict “8 less than Ritu now.”

Common Pitfalls:Subtracting 8 from x (past) instead of from Ritu’s present age (x + 3).

Final Answer:x - 5

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