First find the amount paid just for the per-minute fee, which is $146 - $20 = $<<146-20=126>>126.

Then divide that number by the per-minute rate to find the number of minutes: $126 / $7 per minute = <<126/7=18>>18 minutes.

# Answer

18
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
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?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
18
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?
train