Backtracking from a fraction statement – Twenty years ago, Antony’s age was half of what his present age is. What is his current age?

Introduction / Context:
This problem is a direct one-variable equation framed around a past fraction of the present age. Such prompts are staples of the “ages” topic and emphasize precise temporal translation.

Given Data / Assumptions:

• Let Antony’s present age be A.
• Twenty years ago his age was A − 20, and it equaled (1/2)A.

Concept / Approach:
Set A − 20 = (1/2)A and solve for A. Do not confuse “half of present” with “half of past.”

Step-by-Step Solution:
A − 20 = (1/2)A.A − (1/2)A = 20 ⇒ (1/2)A = 20 ⇒ A = 40.

Verification / Alternative check:
Twenty years ago: 40 − 20 = 20, which indeed is half of 40.

Why Other Options Are Wrong:
Substituting 20, 35, 30, or 25 fails the defining equation.

Common Pitfalls:
Writing 20 years ago as “A/2 − 20” (incorrect) or misplacing the half on the wrong side of the timeline.

Final Answer:
40 years