Six bells toll at intervals of 2, 4, 6, 8, 10 and 12 seconds. In 30 minutes, how many times do they toll together?
A4
B10
C15
D16
Answer & Solution
Correct answer: D. 16
1. They toll together every LCM(2,4,6,8,10,12) = 120 seconds.
2. In 30 minutes = 1800 seconds, number of intervals = 1800/120 = 15.
3. Counting the initial toll (t=0), total tolls together = 15 + 1 = 16.
_Source: KMAT Karnataka 2021 PYQ Q.35_
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