Question

Four bells ring at an interval of 15,20,25 and 30 minutes. All the four bells rang together at 12 noon. At what time they again will ring together?

Answer 1

Answer:

take out LCM of first and second numbers

Answer 2

Answer:

5:00 pm

Explanation:

We have to find a time after which all four bells ring so for this we will take out the LCM:

15=3*5

20=2*2*5

25=5*5

30=2*3*5

Therefore LCM(15,20,25,30)=2*2*3*5*5=300

They will ring after 300 mins or 5 hrs (300 MINS=5 HRS)

Hence time at which they'll ring again= 12 noon + 5 hrs

                                                               =5:00 PM