Question

The total of the ages of A, B, and C is 80 years. What was the total of their age three years ago?

• A. 71 years
• B. 72 years
• C. 77 years
• D. 79 years

Hint:

For age-related problems, always subtract the total years from the current sum based on the number of years ago.

Answer 1

The Correct Option is B

Let the present ages of A, B, and C be:
A = $a$ years
B = $b$ years
C = $c$ years
According to the question, \[ a + b + c = 80 \quad \text{(Total current age)} \] Now, three years ago, each person was 3 years younger. So their ages three years ago would be:
A = $(a - 3)$ years
B = $(b - 3)$ years
C = $(c - 3)$ years
So, their total age three years ago: \[ = (a - 3) + (b - 3) + (c - 3) = (a + b + c) - 9 = 80 - 9 = \boxed{72 \, \text{years}} \]