Question

Traffic light at one particvular crossing changes after every 40 sec. The traffic light at the next crossing changes after every 32 sec. At a certain time thyey change together. After what time will they again change together?

Answer 1

L.C.M of 40 and 32=160
Hence after 160 sec they will change again together

Answer 2

Solution :-

To find the time at which they will again change together, we have to compute the L.C.M. of 32 and 40.

32 = 2*2*2*2*2

40 = 2*2*2*5

L.C.M. of 32 and 40 = 2*2*2*2*2*5 

= 160 Second

So, after 160 seconds or 2 minutes and 40 seconds, the two traffic lights will again change together.

Answer.