Question

Four bells tolls at an interval of 8,12,15 &18 second a respectively. How many times will they toll together in one hour excluding the one at the start?

Answer 1

This is the same as asking for the highest common multiple
8= 4x2
12 = 4x3
15 = 3x5
18 = 3x3x2
so we need: 2x2x2x3x3x5 = 360
they will toll together every 360 seconds
in 1 hour there are 3600 seconds
so they will toll at
360 s, at 720 s, ... at 3600 s

that would be 10

(we are supposed to exclude the toll right now)

Answer 2

10

Answer 3

8=4*2
12=4*3
15=3*5
18=3*3*2
HCF: 2*2*2*3*3*5
=360

1 Hour = 3600 sec
i.e no. of tolls= 3600/360
=10
Therefore, no of tolls = 10

Answer 4

360

Answer 5

Very cheap question