Discussion of Question with ID = 132 under Clocks-and-Calendars

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Question

Two watches, one of which gained at the rate of 1 min. and the other lost at the rate of 1 min. daily, were set correctly at noon on the 1st Jan., 1987. When did the watches indicate the same time?

A

Dec. 27, 1987 mid-night.

B

Dec. 27, 1987 noon.

C

Dec. 28, 1987 noon.

D

Dec. 24, 1987 noon.

Soln.
Ans: b

The first watch gains on the second watch 1 + 1 =2 min. in a day. The watches will indicate same time when one has gained 12 hours on the second. As 2 minutes are gained in 1 day. So 12 hours are gained in = 12 x 12 x 60 = 360 days. Counting 360 days from 1st Jan. 1987 we get Dec. 27, 1987.