Traffic Lights

To determine when the lights synchronize, we have to find the LCM of 48,72 and 108.

$\text{lcm}(48, 72, 108) = 432.$

This means that the traffic lights will change again after 432 seconds, which is equivalent to 7 minutes and 12 seconds. So if they change simultaneously at 9am, then they will change again at 9:07:12am.

We'll have to find $\text{lcm}(48, 72, 108)$ . First, factor every number to figure out which factors are needed.

$48 = 2^4 \cdot 3 \\ 72 = 2^3 \cdot 3^2 \\ 108 = 2^2 \cdot 3^3$

We then take the highest power of each prime factors across 48, 72, and 108. In this case, that would be $2^4$ and $3^3$ . We then multiply them to obtain 432. So, $\text{lcm}(48, 72, 108) = 432.$

This means the traffic lights again will simultaneously change after 432 seconds or at 9:07:12am.

I converted the seconds into fractional minutes. So 48 seconds becomes 4/5 of a minute. 72 seconds becomes 6/5 and 108 seconds becomes 9/5. Now you can solve the LCD in your head. The LCD of 4, 6, and 12 is 36. 36/5 = 7-1/5 minutes or 7 minutes 12 seconds. So if they all change simultaneously at 9, they will change again 7 minute 12 seconds later or at 9:07 12s

LCM of 72, 48, and 108 is 432. 432 divided by 60 (to find the number of minutes) is 7.2. .2 multiplied by 60 (to find the number of seconds) is 12. The answer is 7 minutes, 12 seconds. 9:00:00 + 0:07:12 = 9:07:12

Simply take the least common multiple of the three numbers and you get 432 secs which makes it 9:7:12

Well, everyone is using the LCM, I don't see it that way at all...

If you think about each traffic light on/off scenario as a function modeling y=sin(ax), a being a real number, and if you simply plot those three (assuming the x=0 is 9 AM) than you'll find that the functions will intersect 432 units from the origin. The units being seconds.

9:00 am + LCM of 48,72, and 108 = 9:07:12 am

We have to fin the LCM of 42, 72, 107.

lcm(48,72,108) = 432 http://www.wolframalpha.com/input/?i=lcm%2848%2C72%2C108%29

Mean, 7 mins and 12 secs.

So, The trafic lights will change simultaneously at 9:07:12 AM

Here the LCM of 48,72 and 108 is 432, (60 *7) + 12 = 432 or 7 mint 12 sec, so the require time is 9 : 7 : 12 ......

LCM of 48, 72 and 108= 2X2X3X3X3X2X2X3=432Seconds=7Minutes 12 Seconds. Thus answer is 9:07:12

lowest common multiple of 48 , 72 , 108 are 432 . then 432 second is 7 minute , 12 second.

WE JUST HAVE TO FIND THE LCM OF 48, 72, 108 i.e. 432, hence the traffic light will glow again together after 432 seconds which is equivalent to 7 minutes and 12 seconds So they will glow again together at 9:07:12

Find the LCM of 48,72,108 That is 432 s = 7.2 min. Therefore after 7.2 min. they will glow simuntaneounsly

by just taking the LCM of these three values , then divide ans by 60 to convert seconds into minutes, and then add these minutes to 9:00 o'clock

LCM of 48, 72 and 108 = 432.

So, the traffic lights will change again after 432 seconds i.e. after 7 minutes and 12 seconds

If they change simultaneously at 9 am, they will change again after 7 minutes and 12 seconds

(at 9:07:12 am)

We have to simply find the LCM of 24,48 and 108 i.e. comes out 432
Now 432 seconds is the time for meeting again at same point.
Thus, if 9 am is start, next meet will be after 432 seconds
432 s = 7min & 12 s

hence at 9:07:12 am

Find the LCM of 48,72,108 That is 432 s = 7.2 min. Therefore after 7.2 min. they will glow simuntaneounsly

the L.C.D OF (48,72.108) IS 12min and 7 sec so 9.07.12

Traffic lights are changing after 48,72,108 secs,taking LCM it is 432 thaqt is 7 mtsand 12 secs. So,after 9 AM ,next signals all at one time will be at 9:07;12 AM Ans K.K.GARG,INDIA

We have to take the LCM of the individuals & thus we find 432s, which is after 9am, they will again simultaneously be lit at 09.07.12 am.

We have to find the LCM of 48,72 and 108 which is 432....That means the traffic lights will change again after 432 seconds from 9am... That is 7 minutes and 12 seconds after 9am....