On a clock dial the minute hand makes one revolution every hour. The hand makes one revolution every 12 hours what time will it be when the two hands coincide between 4:00 and 5:00

At exactly 4:00, the minute and

hour hands are 120º apart. The

minute hand travels 360º in 60

minutes, or 6º per minute.

The hour hand travels 360º in

12 hours = 720 minutes, or 1/2 º

per minute. So the minute hand

is catching up to the hour hand

at 5.5º per minute. That works out

to 120 / 5.5 = 21 9/11 minutes, or 21.82 minutes

so Thus they meet at 4:21.82