RRB Junior Engineer Stage 1 Model Papers 3

Question : 9 of 100

Marks: +1, -0

The traffic lights at three different road crossings change after 24 seconds, 36 seconds and 54 seconds respectively. If they all change simultaneously at 10 : 15 :00 AM, then at what time will they again change simultaneously?

10 : 16 : 54 AM
10 : 18 : 36 AM
10 : 17 : 02 AM
10 : 22 : 12 AM

Validate

Solution:

LCM of 24, 36 and 54 seconds = 216 seconds = 3 minutes 36 seconds
∴ Required time

= 10 : 15 : 00 + 3

minutes 36 seconds = 10 : 18 : 36 a.m.

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