Question

Cells Are Us charges $5 per month and$1.50 per minute on their prepaid plan. The total cost for a cell bill can be represented by the equation C = 1.5m + 5, where m represents the number of minutes and C represents the cost, in dollars.

Call Time charges $15 per month and$0.50 per minute on their prepaid plan. The total cost for a cell bill can be represented by the equation C = 0.5m + 15, where m represents the number of minutes and C represents the cost, in dollars.

1. At how many minutes do the two companies charge the same amount?

2.What is the cost, in dollars, when the charge is the same?

1. dangkhoa
1. 10
2. \$20
Step-by-step explanation:
You can use elimination to solve this.
1. Take the equation C=0.5m +15 and multiply the whole thing by -3
3(C=0.5m+15)
-3C=-1.5-45
2. Now add the new equation to C=1.5m+5
-3c+c=-2c
1.5m-1.5m=0
-45+5=-40
You get the equation -2c=-40
3. From this equation you can find the value of c, which is 20.
4. The value of C is the cost for when the charge is the same.
5. Plug in C into any of the equations (I chose c=1.5m+5)
20=1.5m+5
15=1.5m
10=m
6. The value of m is the number of minutes for when they are combined.