Question

Four bells toll at intervals of 4, 7, 12 and 84 seconds. The bells toll together at 5 o'clock. When will they again
together? How many times will they do it in 28 minutes?​

Answer 1

Answer:

In 28 mins they toll (together) 20 times.

Step-by-step explanation:

They will toll together for a 'common multiple' of (4,7,12,84), which is the l.c.m of these numbers.

4 = $2^{2}$

7  = 7

12 = * 3

84 = 12 * 7 = * 3 * 7

l.c.m (4,7,12,84) = $2^{2}$ * 3 * 7 = 84 s

84 s = 1 min 24 sec

Hence they will toll together 84 seconds after 5 o'clock or 5:01:24 hrs ( 1 min 24 sec past 5 o'clock)

28 mins = 28*60 = 1680 sec

84 sec = toll 1 time

1680 sec = X times

X = 20 times

Hence,

They toll together at 5:01:24 hrs

In 28 mins they toll (together) 20 times.

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brainliest plzz......

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