Gnuff charges a flat rate of $20 per tutoring session plus $7 per minute. The total amount paid for Gnuff for tutoring for one session is $146. How many minutes did Gnuff tutor for?
How much is the per-minute fee? ** First find the amount paid just for the per-minute fee, which is $146 - $20 = $<<146-20=126>>126.
How many minutes did Gnuff tutor for? ** Then divide that number by the per-minute rate to find the number of minutes: $126 / $7 per minute = <<126/7=18>>18 minutes.
#### 18