Question

The function f(x) = 2x2 + 2 represents the rate of a bus traveling in miles per hour. The function g(x) = x + 2 represents the time the bus traveled in hours. Solve (f • g)(3), and interpret the answer.

(f • g)(3) = 100, the distance in miles the bus traveled
(f • g)(3) = 100, the number of buses
(f • g)(3) = 25, the distance in miles the bus traveled
(f • g)(3) = 25, the number of buses

Answer 1

The function f(x) = 2x2 + 2 represents the rate of a bus traveling in miles per hour. The function g(x) = x + 2 represents the time the bus traveled in hours. Solve (f • g)(3), and interpret the answer.

Answer:

A) (f • g)(3) = 100, the distance in miles the bus traveled

(Took the exam)

Answer 2

(f • g)(3) = 100, the distance in miles the bus traveled

Explanation:

The product of (miles/hour) and (hours) is (miles), so only answers with units of distance are applicable. The numbers are ...

f(3) = 2·3² +2 = 20 . . . . miles per hour

g(3) = 3+2 = 5 . . . . hours

so (f·g)(3) = f(3)·g(3) = 20·5 = 100 . . . . miles

This means only the first answer choice is applicable.