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Asked by Prabhu

Sep 16, 2013

A traffic light at three different road crossing change

A traffic light at three different road crossing change after every 48 seconds,72 seconds and 108 seconds respectively. If they change simultaneously at 7.00 a.m at what time will they change simultaneously again.?

Answers(5)

Answer

Syeda

Member since Jan 25, 2017

Answer.

Given that traffic light at three different road crossing change after every 48 seconds,72 seconds and 108 seconds respectively.
48 = 2 × 2 × 2 × 2 × 3
72 = 2 × 2 × 2 × 3 × 3
108 = 2 × 2 × 3 × 3 × 3
Hence LCM of 48, 72 and 108 is (2 × 2 × 2 × 2 × 3 × 3 × 3)
 = 432
That is after 432 seconds they will change simultaneously
432 seconds = 7 min 12 seconds
Thus the traffic lights change simultaneously at 7:7:12 am

Tejaswi

462

Ayush Singh

Given that traffic light at three different road crossing change after every 48 seconds,72 seconds and 108 seconds respectively. 48 = 2 × 2 × 2 × 2 × 3 72 = 2 × 2 × 2 × 3 × 3 108 = 2 × 2 × 3 × 3 × 3 Hence LCM of 48, 72 and 108 is (2 × 2 × 2 × 2 × 3 × 3 × 3) = 432 That is after 432 seconds they will change simultaneously 432 seconds = 7 min 12 seconds Thus the traffic lights change simultaneously at 7:7:12 am

Anmol Saket

Changing of traffic light at three different road=1st road=48 seconds
                                                                  2nd road=72 seconds
                                                                  3rd road=108 seconds
LCM of 48, 72 & 108=2*2*3*2*2*3*3
                             =432 seconds
432=432/60 minutes
     =7 minutes 12 seconds.
They will change simultaneously at 7:00 a.m + 7 minutes 12 seconds= 07:07:12 A.M.

They will change simultaneously at 07:07:12 A.M.

Kishore Kumar

Given that traffic light at three different road crossing change after every 48 seconds,72 seconds and 108 seconds respectively.
48 = 2 × 2 × 2 × 2 × 3
72 = 2 × 2 × 2 × 3 × 3
108 = 2 × 2 × 3 × 3 × 3
Hence LCM of 48, 72 and 108 is (2 × 2 × 2 × 2 × 3 × 3 × 3)
 = 432
That is after 432 seconds they will change simultaneously
432 seconds = 7 min 12 seconds
Thus the traffic lights change simultaneously at 7:7:12 am
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