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X 2.4.75

The telephone company offers two billing plans for local calls. Plan 1 charges $36 per month for unlimited calls and Plan 2 charges $17 per month plus $0.04 per call.

a. Use an inequality to find the number of monthly calls for which Plan 1 is more economical than Plan 2

b. Explain the meaning of the answer to part a.

Answer: a. 36-17 <0.04x ⇒ 475 < x

b. When the number of calls is higher than 475, Plan 1 is more economical than Plan 2.

Step-by-step explanation:

Hi, to answer this question we have to write an inequality:

The cost of plan 1 (36) must be less (<) than the cost of plan 2 (fixed charge [17] plus the product of the charge per call [0.04] and the number of calls [x])

a. 36 < 17 + 0.04x

Solving for x

36-17 <0.04x

19 < 0.04x

19 / 0.04
475 < x

b. When the number of calls is higher than 475, Plan 1 is more economical than Plan 2.