Difference between a number divided by three and four is 20

The difference between a number divided by 3 and 4 is 20.

- = 20

multiply by 12

4n - 3n = 12 (20)

n = 240 is the number

and,

Aubrey has $120 to spend on a tennis racket and lessons.

The racket costs $45 and the lessons cost $15/hr.

How many hours of lessons can she afford?

hrs =

hrs = 5 hrs