I need help with this algebra problem.

Question

The telephone company offers two types of service. With plan A, you can make an unlimited number of

local calls per month for $18.50. With Plan B, you pay $6.50 monthly, plus 10 cents for each min of calls after

the first 40 minutes. At least how many minutes would you have to use the telephone each month to make Plan A the better option?

Answer 1

A: $18.50

B: $6.50 + (m - 40)(0.10)

A < B

18.50 < 6.50 + (m - 40)(0.10)

Can you solve for m and answer?

Answer 2

18.50 = 6.50 + .10(M-40) for M>40

12 = .1M -4

16= .1M

M = 16/.1 = 160 minutes when they cost the same

more than 160 and Plan A is cheaper

less than 160 and Plan B is cheaper