Justin wants to paint his room. So he put together some
quotations from two different painters. The first painter's total charge was
based on the number of hours (denoted as x) worked was modeled as
f( x ) = 70 + 5 x, while that of the second painter was
g( x ) = 30 + 15 x. Justin knows that it will take more than 4
hours to decorate the house so he was certain to go with the first painter
whose cost is low-priced when the number of hours is above 4 hours.
