Question

The function f(x) = 0.11x + 43 relates how much Derek pays for phone service, f(x), to the number of minutes, x, used for international calls in a month. What is the value and meaning of f(320)?

Answer 1

Explanation:

To find the value, put 320 where x is and do the arithmetic.

f(320) = 0.11·320 +43 = 35.20 +43 = 78.20

The meaning is described by the problem statement:

"how much Derek pays for phone service" for "the number of minutes, [320], used for international calls in a month."

Derek pays 78.20 for 320 minutes of international calls in a month.

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The units (dollars, rupees, euros, pounds, ...) are not specified.

Answer 2

Answer:

Given the function f(x) = 0.11x + 43, this shows the relationship between how much Derek has to pay for phone service for the amount of minutes he uses on international calls a month.  f(320) can be solved by substituting x = 320, and this is shown below: f(x) = 0.11x + 43 f(320) = 0.11(320) + 43 f(320) = 78.2 This means that Derek has to pay $78.20 for the 320 minutes of calls. Among the choices, the correct answer is B.