A) 12 mid night
B) 3 am
C) 6 am
D) 9 am
Correct Answer: D
Solution :
\[1\frac{1}{2}\]h = 90 min 1 h and 45 min = 105 min 1 h = 60 min \[\therefore \]LCM of 30 min, 60 min, 90 min and 105 min \[\therefore \]LCM\[=3\times 5\times 2\times 2\times 3\times 7=1260\]min 1260 min\[=\frac{1260}{60}=21\,\,\text{h}\] \[\therefore \]The bell will again ring simultaneously after 21 h. \[\therefore \]Time will be = 12 noon + 21 hours = 9 amYou need to login to perform this action.
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