Linear equations in ages – A is 16 years older than B, and half of B’s age equals one-third of A’s age. Find their present ages.

Difficulty: Medium

Correct Answer: A = 48, B = 32

Explanation:


Introduction / Context:
Here we mix an additive relation (“older by 16”) with a fractional comparison (“half equals one-third”). Such systems are best handled with two equations in two variables, then solved by substitution or elimination.



Given Data / Assumptions:

  • A = B + 16.
  • (1/2) * B = (1/3) * A.
  • All ages are present ages.


Concept / Approach:
Convert the fractional statement to an equation without fractions. From (1/2)B = (1/3)A, multiply both sides by 6 to get 3B = 2A. Substitute A = B + 16 into 3B = 2A and solve for B, then back-solve for A.



Step-by-Step Solution:
3B = 2A.With A = B + 16 ⇒ 3B = 2(B + 16) = 2B + 32.Thus B = 32, and A = B + 16 = 48.



Verification / Alternative check:
(1/2)B = 16 and (1/3)A = 16, so the fractional condition holds. The 16-year difference also holds: 48 − 32 = 16.



Why Other Options Are Wrong:

  • 40/32 does not satisfy 3B = 2A.
  • 46/30 and 32/16 violate one or both constraints.
  • “None of these” is not needed because 48/32 is consistent.


Common Pitfalls:
Misreading “half B equals one-third A,” or subtracting 16 in the wrong direction. Keep the algebraic mapping faithful to the words.



Final Answer:
A = 48, B = 32

More Questions from Problems on Ages

Discussion & Comments

No comments yet. Be the first to comment!
Join Discussion