Q163
The traffic lights at three different signal points change after every 45 seconds, 75 seconds and 90 seconds respectively. If all change simultaneously at 7:20:15 hours, then they will change again simultaneously at = ?
A.
7:28:00 hours
B.
7:27:45 hours
AnswerC.
7:27:30 hours
D.
7:27:50 hours
Answer: Option B
Solution
Answer: Option B
Solution:
LCM of 45, 75, 90 is 450∴ Traffic lights will change simultaneously after 7 minutes 30 seconds i.e., at 7:27:45 hours