Question

The function f(x) = 2x + 210 represents the number of calories burned when exercising, where x is the number of hours spent exercising.
The function g(x) = 2x + 125 represents the calorie deficit that occurs when following a particular diet, where x is the number of hours spent exercising.

What is (f + g)(3)? Explain.

347 calories burned while combining diet with 3 hours of exercise.
347 calories burned while dieting for 3 hours.
216 calories burned while exercising for 3 hours.
216 calorie calories burned when combining diet with 3 hours of exercise.

Answer 1

Hi,

f + g is a simple sum of the functions. This refers to increasing the good effect of exercise with diet effect, therefore more weight could be lost.

(f + g)(x) = f(x) + g(x) = 2x + 210 + 2x + 125 = 4x + 335, so (f + g)(x) = 4x + 335.

For x = 3 (meaning 3 hours of exercise) we have:

(f + g)(3) = 4·3 + 335 = 12 + 335 = 347 calories, after 3 hours of exercice.

The correct answer is: 347 calories burned while combining diet with 3 hours of exercise.

Have you understood ?

Green eyes.