Question

3 bells toll together at 10 am . they toll after 7,8 and 11 seconds respectively. how many times will they toll together again in the next 3 hours

5 times
10 times
17 times
20 times

please answer fast​

Answer 1

Answer:

5 times

Step-by-step explanation:

After every 1848 secs, they will toll together. So, The sequence will be 9:00 AM , 9:31 AM , 10 : 02 AM , 10:33 AM, 11:04 AM , 11: 35 AM… Thus, in the 3 hours, the bells will toll together 5 times.

Answer 2

Given,

$3$ bells toll together at $10am$.

Each bell toll after $7, 8$ and $11$ seconds respectively.

Let us find the L.C.M. of the above intervals.

The L.C.M of $7, 8$ and $11$ is $616$ seconds.

Let us convert the $3$ hours into seconds$=3\times60\times60=10,800$ seconds.

Then, the number of times that three bells toll together$=\frac{Time period(10,800sec)}{L.C.M. of given intervals of 3 bells}$

$=\frac{10,800}{616}$

$=17.53=17$ times.

Hence, three bells will toll together for $17$ times in the next $3$ hours.