Question 156247
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 min. At least how many min would you have to use the telephone each month to make Plan A the better option?
:
Let m = no. of minutes used
:
PlanA cost = 18.50
:
PlanB cost = .10(m-40) + 6.50
:
PlanB > PlanA
.10(m-40) + 6.50 > 18.50
:
.10m - 4 + 6.50 > 18.50
:
.10m + 2.50 > 18.50
:
.10m > 18.50 - 2.50
:
.10m > 16.00
m > {{{16/.10}}}
m > 160 minutes
:
We can say if you exceed 160 min, PlanA is the better deal
:
Check this using 161 min in PlanB
C = .10(161-40) + 6.50
C = .10(121) + 6.50
C = 12.10 + 6.50
C = 18.60, ten cents more than PlanA