Question

Bart can fix 6 flat tires in 1 hour. Art can fix 16 flat tires in 3 hours. Today, they have to fix 68 flat tires. How long will it take them if they work together?

Answer 1

In one hour, Bart fixes 6 flat tires.

In one hour, Art fixes 16/3 flat tires.

In one hour both working together fix:

$6+\frac{16}{3}=\frac{34}{3}$

34/3 tires in one hour.

This means that to fix 68 flat tires, they will need:

$\frac{68}{\frac{34}{3}}=68\cdot\frac{3}{34}=6$

Answer: 6 hours