Question

For her phone service, Lisa pays a monthly fee of $27, and she pays an additional $0.05 per minute of use. The least she has been has been charged in a month is $90.70. What are the possible number of minutes she has used her phone in a month? Use m for the number of minutes, and solve your inequality for m.

Answer 1

The equation to find the amount of money spent is 27 + 0.05m. This equation, in this case, needs to be larger or equal to 90.70. So our inequality would be:

27 + 0.05m >= 90.70

Now we can solve this equation for m.

27 + 0.05m >= 90.70
0.05m >= 63.70
m >= 1274