Frank owns a clothing store that sells shorts and graphic T-shirts. He sells the shorts for $14 each and the T-shirts for $6 each. He is limited to the constraints shown by the set of inequalities below. Which of the points (s, t) will maximize Frank's revenue? s≤ 18-0.5t
s≥ 10-t
s≤ 30-t
s≥0
t≥0