How to find equation from given data? (2 phone pricing plans)

[tantrik]

Dear friends,

I am unable to solve the following problem. Will appreciate your help here. Thanks in advance.

The Purple Mobile Phone Company offers the following two pricing plans to customers. Plan-A costs $15/month, with calls at 25c/minute, while Plan-B costs $100/month with calls at 14c/minute. Find an equation that gives C, the cost in dollars, in terms of t, the call time in minutes per month for each plan.

 

[stapel]

The Purple Mobile Phone Company offers the following two pricing plans to customers. Plan-A costs $15/month, with calls at 25c/minute, while Plan-B costs $100/month with calls at 14c/minute. Find an equation that gives C, the cost in dollars, in terms of t, the call time in minutes per month for each plan.

When you're not sure of the final answer, try plugging numbers in, and seeing what patterns you can find. For instance:

In Plan A, if the user makes no calls at all, how much does he pay?

If he makes 1 minute of calls, how much does he pay?

If he makes 10 minutes of calls, how much does he pay?

If he makes 25 minutes of calls, how much does he pay?

If he makes "t" minutes of calls, how much does he pay?

Please reply with your answers to the above, showing your work. Thank you!

 

[tantrik]

When you're not sure of the final answer, try plugging numbers in, and seeing what patterns you can find. For instance:

In Plan A, if the user makes no calls at all, how much does he pay?

If he makes 1 minute of calls, how much does he pay?

If he makes 10 minutes of calls, how much does he pay?

If he makes 25 minutes of calls, how much does he pay?

If he makes "t" minutes of calls, how much does he pay?

Please reply with your answers to the above, showing your work. Thank you!

Thanks for your hint. I could get the answer for the problem. For plan A: C = 0.25t + 15; for plan B: C = 0.14t + 100