Question

Four gongs strike at interval of 30, 60, 90 and 150 minutes respectively. At what time they strike together again next, if they start simultaneously at 12 noon

Answer 1

Answer:

HCF of 30,60,90 and 150

=450

so from 12 noon it will take 450 min more time they strike together again next

now 450 min =450/60=7h30 min

so next they strike together at 7:30 P.M

Answer 2

Answer:

3 am is the right answer ok