Five bells begin to toll together and toll respectively at intervals of $6, 5, 7, 10$ and $12$ seconds. How many times will they toll together in one hour excluding the one at the start?

7

times

No worries! We‘ve got your back. Try BYJU‘S free classes today!

8

times

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

9

times

No worries! We‘ve got your back. Try BYJU‘S free classes today!

11

times

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is D $8$ times
L.C.M. of $6, 5, 7, 10$ and $12$ is $420$ .
So, the bells will toll together after every $420$ seconds i.e. $7$ minutes.
Now, $7 \times 8 = 56$ and $7 \times 9 = 63$ .
Thus, in $1$ -hour (or $60$ minutes), the bells will toll together $8$ times, excluding the one at the start.

Suggest Corrections

Similar questions

Q. Five bells begin to toll together and toll respectively at intervals of 6,5,7,10 and 12 seconds How many times will they toll together in one hour excluding the one at the start?

Four Bells toll together at $9 : 00$ A.M .They toll after $7, 8, 11$ and $12$ seconds respectively . How many times will they toll together again in the next $3$ hours?

5

bells start tolling together and toll at intervals of

2, 4, 6, 8

and

10

seconds, respectively. How many times do the five bells toll together in

20

minutes?

Q. Six bells commencing tolling together toll at intervals of

2, 3, 6, 8, 10

and

12

seconds respectively. In

30

minutes how many times do they toll together?

Join BYJU'S Learning Program

Five bells begin to toll together and toll respectively at intervals of 6,5,7,10 and 12 seconds. How many times will they toll together in one hour excluding the one at the start?

The correct option is D 8 timesL.C.M. of 6,5,7,10 and 12 is 420.So, the bells will toll together after every 420 seconds i.e. 7 minutes.Now, 7×8=56 and 7×9=63.Thus, in 1-hour (or 60 minutes), the bells will toll together 8 times, excluding the one at the start.

Five bells begin to toll together and toll respectively at intervals of $6, 5, 7, 10$ and $12$ seconds. How many times will they toll together in one hour excluding the one at the start?