You are choosing between two different cell phone plans

Question

You are choosing between two different cell phone plans. The first plan charges a rate of 25 cents per minute. The second plan charges a monthly fee of $34.95 plus 12 cents per minute. What is the minimum number of minutes you would have to use in a month in order for the second plan to be preferable?

Answer 1

The first plan Let X = number of minutes used 

The payable amount = 0.25 * X ( in $) 

In Plan second 

Payable amount 

= 34.95 + X*0.12

For the two to be equal 

X = 268.11

So cost for 269 calls in first plan = $ 67.25 and second plan = $ 67.23