Question

school bell rings every 12 minutes another school bell rings every 9 minutes in how many minutes will they ring at the same time ? give the answer in step by step?​

Answer 1

Answer:

Explanation:

So first you find the LCM, or least common multiple, (can be called LCD, least common denominator).

The LCM of

20

,

30

, and

50

is basically

10

⋅

2

⋅

3

⋅

5

because you factor out the

10

since that is a common factor.

10

⋅

2

⋅

3

⋅

5

=

300

This is the number of minutes. To find the number of hours, you simply divide by

60

and get

5

hours. Then you count

5

more hours from

12:00 pm

and get

5:00 pm

.

Answer 2

Answer:

36 minutes

Step-by-step explanation:

Take LCM of 12 & 9

you will see that both the bells ring at 36 minutes

 Multiples of 12= 12 , 24 , 36 , 48 .60 , 72

 Multiples of  9 = 9 ,18 ,27 ,36 ,45 ,54, 63, 72

  Common multiples are    36, 72, ........

Least Common Multiple (LCM) =36

Therefore the two bells will ring together in 36 minutes