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