Question

in a school the duration of period in junior section is 40 min and in senior section is 60 min if the first bell for each section rings at 9.am, when will the two bell rings together again​

Answer 1

Answer:

junior section

first bell= 9:00am

second bell = 9:40am

third bell = 10:20am

fourth bell = 11: 00am.

senior section

first bell=9:00am

second bell =10:00 am

third bell= 11:00 am

two bell ring each other at 11: 00 am

Answer 2

just take the LCM (least common multiple) of 40 & 60 it's 120. So the bell will ring after 2 hours i.e 11 am