$171-$35=$136 (minus out the call out fee since it's only paid once)
$136=the amount of all the hours.
$32= amount per hour
therefore:
$136÷$32 = 4.25 hours.
demical forms to minutes:
0.25 × 60 minutes =15 minutes
4 hours + 15 minutes = 4 hour 15 minutes
