Question

The traffic signals at four road crossing change
every 30 second, 1 minute, 45 seconds and 75
seconds respectively. If they change
simultaneously at 9 AM, at what time will they
change simultaneously again.​

Answer 1

For this question we should take lcm

*1 minute is 60*

lcm of 30,60,45,75 = 900sec

convert to minutes = 900/60

= 15 minutes

after 9 am means add 15

which is 9.00 + 15 = 9: 15

it will change simultaneously again in 9:15 AM( anti meridian)

Hope this answer helps you,

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