Answer:
The oldest person is 25 years old
Step-by-step explanation:
Represent David's age by d.
Then Dan's age is d + 5, and Bridget's is d - 8.
The sum of these three ages is 57:
d + (d + 5) + (d - 8) = 57
This simplifies to
3d - 3 = 57, or 3d = 60. Then d must be 20.
David is 20, Dan is 25 (5 years older than David), and Bridget is 12 (8 years younger than David).
Check: Do these three ages add up to 57?
20 + 25 + 12 = 57 YES\
The oldest person is 25 years old. That's Dan's age.
