Question

a light blinks after every 3 seconds another light blinks after 5 seconds and the third one blinks after every 16 seconds. how many times do they blink together in half an hour

Answer 1

Step-by-step explanation:

120 times do they blink together in half an hour.

Step-by-step explanation:

Given : A light blinks after every 3 seconds, another light blinks after every 5 seconds.

To find : How many times do they blink together in half an hour.

Solution :

According to question,

We take the LCM of 3 and 5

i.e, LCM(3,5)=15

1 hour = 60 minutes = 3600 seconds

\frac{1}{2} hr=\frac{3600}{2}s21hr=23600s

\frac{1}{2} hr=1800s21hr=1800s

Times in 30 mins= \frac{1800}{15}=120151800=120

Therefore, 120 times do they blink together in half an hour.