Question

There are three bells. Bell A ring every 5 minutes, Bell B rings every 10
minutes and bell C rings every 15 minutes. The bells ring together at 12:40pm.
a) Write the H.C.F means.
b) Find the two common multiples of 10 and 15.
c) When the next time they will ring together?​

Answer 1

Step-by-step explanation:

In order to find when all three will ring together again. We have to find the LCM of 3,6 and 15

3=3

6=2×3

15=3×5

Therefore, LCM of 3,6 and 15 is

LCM=2×3×5=30

Hence, All three bell will ring together after 30 Minutes ,i.e.,at 1:10pm

Answer 2

a. HCF:Step-by-step explanation:

5=1×5                                                                                                                           10=5×2                                                                                                                      15=5×3                                                                                                                       COMMON FACTOR IS 5,                                                                                          HENCE THE HCF:5                                                                         b.10=10,20,30,40,50,60,70,80,90.....                                                                     15=15,30,45,60,75,90........                                                                                       FIRST TWO COMMON ACTORS ARE 30 AND 60                                         c.12:40 adding 5, 5 minutes comes 12:45,12:50.12;55,1:00,1:05,1:10.......              12:40 adding 10,10 minutes comes 12:50,1;00,1;10,1;20.............                            12;40 adding 15,15 minutes comes 12:55, 1:10,1:25...................                                 the first common number is 1:10                                                                               hence,the next time it will ring at 1:10pm