Question

Possible number of learners in the

in a village, the bell rings every 30 minutes at the Junior School and every 40
minutes at the High School Both schools start lessons at 8:00 am
At what times between 8.00 am and 2.30p.m do the bells both rring

Answer 1

Solution :-

At first common multiple of 30 an 40

`\sf \to \: 30 = 30,60,90,120`

`\sf \to \: 40 = 40,80,120`

Common Multiple = 120

Time taken = 120/60 = 2 hrs

Now,

8.00 + 2 = 10.00 am

10.00 + 2 = 12.00 noon

12.00 + 2 = 2.00 pm

`\\`

Answer 2

Find multiples of 30 and 40:

30: 30, 60, 90, 120, 150

40: 40, 80, 120, 160

The least common multiple is 120, so every 120 minutes they willl both ring.

1 hour = 60 minutes:

120/60 = 2 hours.

The bells ring together every 2 hours.

8 + 2 = 10 am

10 + = 12pm

12 + 2 = 2 pm

The bells will ring together at am, 12 pm and 2 pm.