Problema Solution
the cost for using a phone card is 35 cents per call plus 25 cents per minute. write an expression for the cost of a call that is n minutes long. a certain call is $3.60. how long was the call?
Answer provided by our tutors
Lets assume we are making a phone call that is n minutes long.
We need to pay:
35 for the call only
25 for 1 minute that is 25 * n for n minutes
We need to add these two together to get the total expense. Thus the expression for the cost of the call that is n minutes long will be
cost = 35 + 25 * n
A certain call was $3.60 = 360 cents that is 35 + 25 * n = 360. We need to find n.
We will find n by solving the equation
35 + 25 * n = 360
25 * n = 360 - 35
25 * n = 360 - 35
25 *n = 325
n = 325 / 25
n = 13 minutes
The $3.60 call was 13 minutes long.