A father is 5 more than 8 times his daughter’s age. If the father is 29 years old, how old is his daughter?

Question

Questioning on how to figure this one out?

Answer 1

You have two unknowns, so you need two equations to solve it.

Let x=father's age

     y=daughter's age

Eq. I:   x=29             given

Eq. II:  x=8y+5

Substituting 29 for x in Eq. II we can solve for y:

           x=8y+5        original equation

          29=8y+5       substitute 29 for x

          29-5=8y        subtract 5 from both sides to isolate the y term

          24=8y           simplify

          24/8=y          divide both sides by 8 to solve for y

           3=y             answer

The age of his daughter is 3.