SOLUTION: For using a computerized financial news network for 45 min during prime time and 80 min during non-prime time, a customer was charged $10.95. A second customer was charged $13.35

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Question 1140808:
For using a computerized financial news network for 45 min during prime time and 80 min during non-prime time, a customer was charged $10.95. A second customer was charged $13.35 for using the network for 60 min of prime time and 90 min of non-prime time. Find the cost per minute for using the financial news network during prime time

Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
x = the price of prime time per minute.
y = the price of non-prime time per minute.

you have two equations that need to be solved simultaneously.

they are:

45 * x + 80 * y = 10.95
60 * x + 90 * y = 13.35

multiply both sides of the first equation by 4 and multiply both sides of the second equation by 3 to get:

180 * x + 320 * y = 43.80
180 * x + 270 * y = 40.05

subtract the second equation from the first to get:

50 * y = 3.75

solve for y to get y = 3.75 / 50 = .075

go back to original equaitons and replace y with .075 and solve for x.

your original equations are:

45 * x + 80 * y = 10.95 becomes 45 * x + 80 * .075 = 10.95
60 * x + 90 * y = 13.35 becomes 60 * x + 90 * .075 = 13.35

in the first equation, solve for x to get x = (10.95 - 80 * .075) / 45 = .11

in the second equation, solve for x to get x = (13.35 - 90 * .075) / 60 = .11

x = .11 in both equations, as it should, if the value of y was calculated correctly.

you have.

cost for prime time = .11 per minute.
cost for non-prime time = .075 per minute.

that should be your solution.

replace x and y in both original equations to confirm they are true when these values are used.

45 * x + 80 * y = 10.95 becomes 45 * .11 + 80 * .075 = 10.95 which becomes 10.95 = 10.95, confirming the solution is good.

60 * x + 90 * y = 13.35 becomes 60 * .11 + 90 * .075 = 13.35 becomes 13.35, confirming the solution is good.

your solution is that the cost for using the financial news network during prime time is 11 cents a minute.