He used an incorrect time ratio converting hours to minutes.
So you know that he earns $15 per hour so we can write that as 15h, h = # of hours worked
We also know he has to earn AT LEAST $200, so putting all this together we form the inequality(=< means less than or equal to): 15h =< 200
so now we have to solve for h (number of hours worked):
15h =< 200
(divide both sides by 15)
h =< 13 1/3
So, the painter must work a minimum of 13 and 1/3 hours to earn at least $200.
