Question

An older person is three years older than eight times the age of a younger person. The sum of their age is 21. Find their ages.

Answer 1

Lets have the younger person be x.
The older person will be 8x + 3.

The sum of their ages is 21, so we can get this equation:

x + (8x+3) = 21

9x+3 = 21
Subtract 3 from both sides
9x = 21

x=3 --> The younger person is 3 years old, and now we can substitute that for the older person (8x+3):

(3 * 8) + 3 = 27

The younger person is 3 years old, and the older person is 27.