Multiple choice

A watch which gained 5 seconds in 3 minutes, was set right at 7 a.m. In the afternoon on the same day, when the watch indicated quarter past 4 o'clock, the actual time was

  1. 5 p.m.

  2. 4 p.m.

  3. 3 p.m.

  4. 2 p.m.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The watch gains 5 seconds every 3 minutes. In 1 hour (60 minutes), it gains 5 * 20 = 100 seconds. From 7 a.m. to 4:15 p.m. is 9 hours and 15 minutes (555 minutes). Total gain = (555/3) * 5 = 185 * 5 = 925 seconds = 15 minutes and 25 seconds. If the watch shows 4:15, the actual time is 4:15 minus 15m 25s, which is approximately 4 p.m.

AI explanation

If the watch gains 5 seconds every 3 minutes, it gains 1 second every minute. When the watch indicates 4:15 p.m., exactly 9 hours and 15 minutes (555 minutes) have passed since 7 a.m. The total time gained is 555 seconds, which is 9 minutes and 15 seconds. Therefore, the actual time is 4:15 minus 9 minutes and 15 seconds, which equals exactly 4 p.m.

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