Abasic cellular phone plan costs $4 per month for 70 calling minutes. additional time costs $0.10 per minute. the formula c= 4+0.10(x-70) gives the monthly cost for this plan, c, for x calling minutes, where x> 70. how many calling minutes are possible for a monthly cost of at least $7 and at most $8?

For a monthly cost of at least $7 and at most $8, you can have between 100 and 110 calling minutes.

Step-by-step explanation:

The problem states that the monthly cost of a celular plan is modeled by the following function:

In which C(x) is the monthly cost and x is the number of calling minutes.

How many calling minutes are needed for a monthly cost of at least $7?

This can be solved by the following inequality:

For a monthly cost of at least $7, you need to have at least 100 calling minutes.

How many calling minutes are needed for a monthly cost of at most 8:

For a monthly cost of at most $8, you need to have at most 110 calling minutes.

For a monthly cost of at least $7 and at most $8, you can have between 100 and 110 calling minutes.

c > -10.55

step-by-step explanation: