Answer:
13 hours
Explanation:
Let's first start by finding how much he makes in 1 hours:

Now we can set up two ratios

Solve by cross multiplying (multiply the numerator of the first fraction with the denominator of the second fraction and the numerator of the second fraction with the denominator of the first fraction)
16x=208
Divide both sides by 16 to isolate x
x=13
He would have to work 13 hours to make $208