Question

Sam works two jobs, one at the zoo and the other at

the library. He drives 24 miles round-trip to the zoo
and 9 miles round-trip to the library. He never works
two jobs in the same day. His car has a 15 gallon
gas tank and gets 20 miles per gallon. If his tank is
now empty and he has worked 12 days at the library
since his last filling up, how many days did he work
at the zoo?

Answer 1

Full tank = 15 gallon
15 x 20 = 300 miles
A full tank can travel 300 miles

12 days at the library:
12 x 9 = 108 miles

The rest of the miles were for going to the zoo
300 - 108 = 192 miles

Number of round trips to the zoo:
192 ÷ 24 = 8

He worked 8 days at the zoo.