Question

Question #dfe82

Answer 1

The call lasted between five and six minutes.

Explanation:

If the call lasts more than `k-1` but less then `k` minutes, the cost is:

`C=0.24 + (k-1)*0.18`

As `C=1.14`:

`1.14 = 0.24+ (k-1)*0.18`

`1.14-0.24 =(k-1)*0.18`

`0.9 =(k-1)*0.18`

`0.9/0.18 = k-1`

`5 =k-1`

`k=6`