Answer
The surgeon will gain $70.
Work Step by Step
Since the surgeon is 10 times faster than the plumber, it will take the plumber 60 minutes (1 hour to clear the drain.) He charges 50 dollars an hour, while the surgeon earns 20 dollars per minute. Hence, it will take her 120 dollars (6 minutes times 20 dollars per minute) to clear the drain. $120 - $50 = $70.
