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A bells toll together at 9:00am. They toll after 7,8,11and12 seconds respectively . How many times will they toll together again in the next 3 hours. |
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Answer» Step-by-step explanation: Bell1 : tolls at t = 0seconds, 7s, 14s, 21s.... 2" 0s, 8s, 16S, 24s,... 3: 0,11,22, 33s,... 4: 0, 12, 24,36,48s,... LCM of 7s , 8s ,11s ,12 is : 7 * 2 *2*2 *11 * 3 = 1848 sec = 30 min and 48 seconds. so we add 30 m 48 sec to the previous time instant that they tolled together. next time all the bells will toll together will be at 9 h 30min 48 sec next time it will be 10 h 1 min 36 sec next it will be at 10 h 32 min 24 sec next it will be at 11 h 3 min 12 sec next it will be at 11 h 34 min 0 sec next it will be at 12 h 04 min 48 sec.. this is after 3 hrs from 9 am. ===> to do it simply: in 180 minutes = 3 hrs, they toll together = 180 min / 30min 48sec times = 5.84 times that is 5 times. Hope it HELPS.... |
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