A phone company offers two option

Question

A phone company , First degree offers an overseas call package $2.50 plus 5cents per min for any other international calls while other company , Vivo phone offer a competitive package by charging a flate rate of 25 cent per min.

 

a. Determine the cheaper package for a single 15 min international calls

 

b. John made an international calls which lasted t min, and realised that he incurred the same costs whatever phone company he chose.  Determine the exact value of t

Answer 1

First:

cost = $2.50 + $0.05m, where m means minutes

 

Vivo:

cost = $0.25m, where m means minutes

 

a. Substitute 15 for m and solve.

 

b. $2.50 + $0.05t = $0.25t, solve for t, John's minutes