Three bells ring at the intervals of 10, 15 and 20 minutes respectively. If
they all ring at 10:00 a.m. at once, at what time will they ring together
again?
Three measuring tapes are of 24 m, 32 m and 48 m long. Find the
Answers
We need the lowest common multiple (LCM) of 10,15,and 20
10 = 2*5
15 = 3*5
20 = 2*2*5
These are the prime factorization for these numbers.
2*2*3*5 = 60 This is the lowest common multiple.
11 am is the answer.
Step-by-step explanation:
In simple way, we need to find the lowest number, which is fully divisible bh 10, 15 and 20. So let's find the PCM of these 3, and that is 60mins.
So 60 minutes after 12 o'clock, all 3 bells will ring together again, ie at 1 o'clock.
Another way, non math way, to solve this is
BellA will ring at 12:00, 12:10, 12:20, 12:30, 12:40, 12:50, 1:00
BellB will ring at 12:00, 12:15, 12:30, 12:45, 1:00
BellC will ring at 12:00, 12:20, 12:40, 1:00
So, after ringing together at 12 o'clock, the bells will again ring together at 1 o'clock.