A is twice as old as B was two years ago. The difference between their present ages is 2 years. Find A’s present age (in years).

Difficulty: Medium

Correct Answer: 8 years

Explanation:


Introduction / Context:
Mixing a present-time difference with a past-time multiplicative relation yields a solvable two-equation system in present ages A and B.


Given Data / Assumptions:

  • A = 2(B − 2)
  • A − B = 2


Concept / Approach:
Substitute the expression for A from the first equation into the second and solve for B; then recover A.


Step-by-Step Solution:

A = 2B − 4(2B − 4) − B = 2 ⇒ B − 4 = 2 ⇒ B = 6A = 2B − 4 = 12 − 4 = 8 years


Verification / Alternative check:
B two years ago = 4; 2 × 4 = 8 = A now; and A − B = 2 holds (8 − 6).


Why Other Options Are Wrong:
12, 14, 18 violate either the difference or the past-time doubling relation.


Common Pitfalls:
Doubling B now instead of B two years ago, or misapplying the 2-year difference sign.


Final Answer:
8 years.

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