Question

A clock chimes every 20mins

Answer 1

Answer: 6 times

Step-by-step explanation:

it is a lowest common multiple question. So we list the multiples

20                   8

40                   16

60                   24

80                   32

                      40

40 is our lowest common multiple. Which means every 40 minutes they flash and chime together.

so if we add 40 minutes onto 08:00 we get 08:40 and if we add it again we get 09:20 and again we get 10:00 and again we get 10:40 and again we get 11:20 and again we get 12:00. We have to stop here as if we add 40 minutes again we will go over the given time of 12:30. If we count how many times it was added. this adds to 6. therefore the answer is 6.  

hope this helped.