Question

In school the first Bell ring after every 30 minutes for primary section the second bell rings after every 40 minutes for middle section and the third will ring after every 45 minutes for senior section if the school starts at 9 a.m. with a bell for all these section then when will the three bells ring together again after 9 a.m.

Answer 1

Time at which bell for all these section will ring together will be equal to the LCM of 30,40 and 45

2 | 30, 40, 45

5 | 15, 20, 45

3 | 3 , 4 , 9

3 | 1 , 4 , 3

2 | 1 , 4 , 1

2 | 1 , 2 , 1

1 , 1 , 1

LCM = 2 × 2 × 2 × 3 × 3 × 5

= 8 × 9 × 5

= 72 × 5

= 360

Hence all three bell will ring together after 360 min

= 6 hr

that is 3 PM

Answer 2

Answer:

here's the answer

Step-by-step explanation:

they will again ring together at 3 pm

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