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Three bells ring simultaneously at 10 a.m. They ring at regular intervals of 20 minutes, 30 minutes and 40 minutes respectively. The time when all the three ring together next is

Three bells ring simultaneously at 10 a.m. They ring at regular intervals of 20 minutes, 30 minutes and 40 minutes respectively. The time when all the three ring together next is Correct Answer 12 p.m.

Given:

Three bells ring at regular intervals of 20 minutes, 30 minutes and 40 minutes respectively.

Calculations:

The time after which they will ring together = L.C.M of their ringing time

L.C.M (20, 30 and 40)

⇒ 120 minutes

⇒ 2 hr

They ring simultaneously at 10 a.m.

∴ They will ring simultaneously 2 hrs after 10 a.m i.e. at 12 p.m.

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