Verbal Reasoning - Arithmetic Reasoning - Discussion

Discussion Forum : Arithmetic Reasoning - Section 1 (Q.No. 26)
26.
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
8 times
9 times
11 times
Answer: Option
Explanation:

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 x 8 = 56 and 7 x 9 = 63.

Thus, in 1-hour (or 60 minutes), the bells will toll together 8 times, excluding the one at the start.

Discussion:
17 comments Page 2 of 2.

Mukhtar said:   8 years ago
My question is, five balls begin to toll together and toll respectively at intervals of 6, 7, 8 and 12 seconds. How many times they will toll together in one hours excluding the one at the start?

A) 3.
B) 5.
C) 7.
D) 9.

Can anyone solve this?

Nidhi said:   8 years ago
Ans is 9.
Lcm is 336.
Now 336 ÷ 60 is 5.6.
5.6 * 10 = 56.
Excluding first term, we get 9.

Siyad said:   8 years ago
Thanks for explaining @Jaspreet Singh.

Siyad said:   8 years ago
@Nidhi.

You are absolutely wrong.

How did you get LCM 336? :(LCM is 420 and answer is 8 times).

Revanth said:   8 years ago
Thank you for the explanation @Jaspreet Singh.

Sourav patra said:   5 years ago
Agree @Sushil Ojha.

Paboh sir said:   4 weeks ago
They will toll together 8 times, including the start, then if we exclude its 8-1 =7 times.
Why the answer is 8 times.
Anyone, clarify to me.


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