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Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
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A watch gains 5 seconds in every hour. If it is set right at 8 AM, what time will it show at 8 PM on the same day?
8:01 PM
8:00 PM
8:02 PM
7:59 PM
8:01 PM
Calculate duration in hours (12 hours) and multiply by gain (5 sec/hr) to get total gain (60 seconds = 1 minute). Add this to the end time.
Watch gains 5 seconds every hour. Start time is 8 AM. End time is 8 PM.
Total Gain=Gain per hour×Total duration in hours
Calculate duration in hours (12 hours) and multiply by gain (5 sec/hr) to get total gain (60 seconds = 1 minute). Add this to the end time.
Students often miscalculate the total time duration, forgetting to count hours from 8 AM to 8 PM as 12 hours total.
Calculate total duration
The time elapsed from 8 AM to 8 PM is 12 hours.
T=12 hours
Calculate total gain
Since the watch gains 5 seconds per hour, for 12 hours the total gain is 12×5=60 seconds.
Total Gain=12×5=60 seconds
Convert gain to minutes
Since 60 seconds equals 1 minute, the watch gains 1 minute in 12 hours.
60 seconds=1 minute
Determine final time
The watch will be 1 minute ahead of the actual time. Adding 1 minute to 8:00 PM gives 8:01 PM.
Final Time=8:00 PM+1 minute=8:01 PM
A is correct because the watch gains 60 seconds (1 minute) over the 12-hour period, resulting in a time of 8:01 PM.
This is a standard clock problem. Always convert the gain/loss rate to the total duration to avoid errors when dealing with fast or slow watches.