Question

A phone company offers two monthly charge plans. In Plan A, the customer pays a monthly fee of $1.90 and then an additional 6 cents per minute of use. In

Plan B, there is no monthly fee, but the customer pays 7 cents per minute of use.

For what amounts of monthly phone use will Plan A Cost than Plan B?
Use m for the numbers of minutes of phone use in a month, and solve your inequality for m.

Answer 1

Explanation:

sadly you skipped the key word in the question.

should we check under what circumstances plan A costs more than plan B ? or costs less than plan B ?

so, I don't know which inequality to solve.

but I can tell you the facts, and you need to pick the right direction for your answer.

cost of plan A for used minutes m :

cA(m) = 1.9 + 0.06m

plan B

cB(m) = 0 + 0.07m = 0.07m

to find the intersecting point, where both plans cost the same :

1.9 + 0.06m = 0.07m

1.9 = 0.01m

m = 1.9 / 0.01 = 190 minutes

up until 190 minutes plan B is cheaper.

if there are more than 190 minutes, than plan A is cheaper.

so,

m < 190 B is cheaper

m > 190 A is cheaper

m = 190 A and B cost the same