Tell the Time ???

At what time after 4.00 p.m. is the minutes hand of a clock exactly aligned with the hour hand?

2 Answers

226
Abhas Agarwal ·

Assume that X minutes after 4.00 PM minute hand exactly
aligns with and hour hand.

For every minute, minute hand travels 6 degrees.

Hence, for X minutes it will travel 6 * X degrees.

For every minute, hour hand travels 1/2 degrees.

Hence, for X minutes it will travel X/2 degrees.

At 4.00 PM, the angle between minute hand and hour hand is
120 degrees. Also, after X minutes, minute hand and hour
hand are exactly aligned. So the angle with respect to 12
i.e. Vertical Plane will be same. Therefore,

6 * X = 120 + X/2

12 * X = 240 + X

11 * X = 240

X = 21.8182

X = 21 minutes 49.5 seconds

226
Abhas Agarwal ·

4:21:49.5

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