The following table shows the charges for making an overseas call to Australia.

1. Calculate the amount paid for the additional minutes

Total paid = $\char36{}32$
Charge for first 15 minutes = $\char36{}2.60$
Amount paid for additional minutes = $\char36{}32 - \char36{}2.60 = \char36{}29.40$

2. Convert the additional amount to cents to match the rate unit

Amount in cents = $29.40 \times 100 = 2940$ cents

3. Formulate the expression for the total duration

Additional minutes = $\frac{2940}{p}$
Total duration = $15 + \frac{2940}{p}$ minutes

1. Substitute $p = 60$ into the expression for the duration of the call

From part (a), the duration is $15 + \frac{2940}{p}$.
Substitute $p = 60$:
$\text{Duration} = 15 + \frac{2940}{60}$

2. Calculate the final duration

$\text{Duration} = 15 + 49 = 64$ minutes