NCERT Solutions for Class 6 Maths Chapter 3
Important NCERT Questions
Playing With Numbers Chapter 3 Exercise 3.7
NCERT Books for Session 2022-2023
CBSE Board
Questions No: 6
The traffic lights at three different road crossings change after every 48 seconds, 72 seconds and 108 seconds respectively. If they change simultaneously at 7 a.m. at what time will they change simultaneously again?
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L.C.M. of 48, 72, 108 = 2 x 2 x 2 x 2 x 3 x 3 x 3 = 432 sec.
After 432 seconds, the lights change simultaneously.
432 second = 7 minutes 12 seconds
Therefore the time = 7 a.m. + 7 minutes 12 seconds
= 7:07:12 a.m.
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