Question

In a school, the duration of a period in junior section is 40 minutes and senior section is 1 hour , if the first bell for each rings at 9:00 am , when will the two bells ring together agaain ?

Answer 1

find the LCM of 40 and 60 .that is 120
so after 120 mins both bells will ring together
it means after 2 hours
9 + 2 = 11 a.m.

Answer 2

Concept-

Find the LCM of 40 and 60 and then find the time at which both bells ring together .

Given-

The duration of a period in junior section is 40 minutes and senior section is 1 hour and the first bell for each rings at 9:00 am .

Find-

When will the two bells ring together ?

Solution-

First bell rings at 9;00 am

The duration of junior section is 40 minutes.

The duration of senior senior section is 1 hour ( 60 minutes).

Factors of 40 = 2³ × 5

Factors of 60=2² × 3 × 5

LCM = 8 × 5 × 3

LCM = 120

So, after 120 minutes both bells will ring together , it means after 2 hours.

i.e. 9 + 2 = 11 am

Therefore, the two bells ring together again at 11 am.

#SPJ2