what is f(r) = 60 - 2/3 r when r =12?
f(r) = 60 - 2/3r r = 12 Substitute r for 12f(12) = 60 - 2/3(12) 12 * 2/3 = 8 f(12) = 60 - 8 f(12) = 52 52 is your answer