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5 bells ring simultaneously at intervals of 4, 5, 8, 9 and 10 seconds. All the bells start ringing simultaneously. When will they play together next time:

5 bells ring simultaneously at intervals of 4, 5, 8, 9 and 10 seconds. All the bells start ringing simultaneously. When will they play together next time: Correct Answer 6 minutes later

Given:

5 bells ring at intervals of 4, 5, 8, 9 and 10 seconds. 

Calculation:

LCM of 4, 5, 8, 9 and 10 

Factor of 4 = 1 × 2 × 2

Factor of 5 = 1 × 5

Factor of 8 = 1 × 2 × 2 × 2

Factor of 9 = 1 × 3 × 3

Factor of 10 = 1 × 2 × 5

LCM (4, 5, 8, 9, 10) = 360

⇒ bells ring together after 360 seconds = 6 minutes

∴ Bells ring together after 6 minutes

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