# Math Help - Word Problem C= 0.25(t-400) + 48.95

1. ## Word Problem C= 0.25(t-400) + 48.95

A cellular phone company offers a contract for which C, in dollars of t minutes of telephone is given by

C= 0.25(t-400) + 48.95

Assuming that t > 400

What times will keep (for the cost) between $90.70 and$129.95

Phone time must be between ________ Min and _______ Min.

What do I have to do first? Estimate the amount of minutes?

2. Hello OneidaFL
Originally Posted by OneidaFL
A cellular phone company offers a contract for which C, in dollars of t minutes of telephone is given by

C= 0.25(t-400) + 48.95

Assuming that t > 400

What times will keep (for the cost) between $90.70 and$129.95

Phone time must be between ________ Min and _______ Min.

What do I have to do first? Estimate the amount of minutes?
You need to solve two equations for $\displaystyle t$, to find the values of $\displaystyle t$ that make $C = 90.70$ and $C = 129.95$.

That is, you need to solve:
$90.70 =0.25(t-400) + 48.95
$
and
$129.95 =0.25(t-400) + 48.95
$

These solutions will give you the minimum and maximum values you require.

Can you complete it now?