The New network cell phone company charges $20 a month for service and $0.02 per minute of talking time. The mobile company charges $15 a month for service and $0.03 per minute of talking time..

Question

(q) write expressions for the total bill of each company (1%).

2) set up an inequality that can be used to determine for what amount of time (in minutes) My mobile is the better plan. (1%).

3) solve your inequality (2%)

4) why did you have to put a restriction on the algebraic solution form part C? (1%).

Answer 1

cost1 = .02m + 25
cost2 = .03m + 15

when is cost2 < cost1 ?
.03m + 15 < .02m + 25
.01m < 10
m < 1000 , so for any time less than 1000 minutes, the second plan is cheaper

Answer 2

1. Y = 20 + 0.02x.
Y = 15 + 0.03x.
x = minutes used.

2. 15 + 0.03x < 20 + 0.02x.

3. 0.03x - 0.02x < 20 - 15,
0.01x < 5,
X < 500 minutes.