Peter started work at 10.30 a.m. and ended work at 6.15 p.m.
How long did he work? Give your answer in hours and minutes. Answer: ___ h ___ min

1. Convert the end time to 24-hour clock format

$6.15 \text{ p.m.} = 1815 \text{ hours}$

2. Calculate the time duration

Duration = $1815 - 1030$
$1815 = 17 \text{ hours } 75 \text{ minutes}$
$17 \text{ h } 75 \text{ min} - 10 \text{ h } 30 \text{ min} = 7 \text{ h } 45 \text{ min}$