For a long distance person to person telephone call a telephone company charges 0.91 for the first minute 0.58 for each additional minute and 2.74 a service charge. If the cost of a call is 5.39 how long did the person talk

If the cost of a call is 5.39, obviously this person stayed more than one minute at the telephone. It will pay for:

If we will find out the value of x, we will know how much time this person paid for additional minutes. Let's make some subtractions:

So, this person paid 1.74 by additional minutes. Let's divide this value by the price for additional minute:

This means that it paid by 3 minutes additional.

Therefore, this people stayed at telephone by 3 + 1 = 4 minutes.