LCM and HCF Practice Test 4

Question : 39 of 40

Marks: +1, -0

Three bells ring respectively at an interval of 15 seconds, 20 seconds and 24 seconds. If they ring continuously for 12 minutes then how many times, during this period, will they ring together?

2 times
6 times
5 times
3 times

Validate

Solution:

LCM of 15, 20 and 24

LCM = 5 × 4 × 3 × 2 = 120
∵ 12 minutes = 12 × 60 = 720 seconds
∴ Number of times the bells will ring together during 12 minutes

= 720/120 = 6

times.

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