SOLUTION: I am trying to write equations to represent two phone plans. One plan is $20 with 30 minutes free and .10 for each additional minute. The second plan is $51 with 100 minutes free
Question 422738: I am trying to write equations to represent two phone plans. One plan is $20 with 30 minutes free and .10 for each additional minute. The second plan is $51 with 100 minutes free and .o4 for each additional minute. Then how can I compare the costs? Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! Write a cost equation for each statement:
:
Let m = no. of minutes used (greater than 100 min)
:
One plan is $20 with 30 minutes free and .10 for each additional minute.
C = .10(m-30) + 20
:
The second plan is $51 with 100 minutes free and .o4 for each additional minute.
C = .04(m-100) + 51
:
Then how can I compare the costs?
:
How many minutes will you have to use to make the 1st plan more expensive than the 2nd plan?
:
1st plan cost more than 2nd plan
.10(m-30) + 20 > .04(m-100) + 51
.10m - 3 + 20 > .04m - 4 + 51
.10m + 17 > .04m + 47
.10m - .04m > 47 - 17
.06m > 30
m >
m > 500 minutes use, will make the 2nd plan a better deal
:
Check this for yourself, assume m = 501 min
:
did this make sense to you?
