traffic light changes every 28 secs, another every 32 secs.

[moto16]

A traffic light at one intersection chnages every 28 seconds. The traffic light at the next intersection changes every 32 seconds. How long before they both change together? I don't know how to figure this ouT!

 

[Loren]

Re: word problem

One way would be to plot it.

28 56 84 112 140 etc.

32 64 96 128 160 etc.

Sooner or later you will find both lists contain the same number(s). Of course you want the smallest (least) one. But, there is a better and more efficient way to get the answer. I'll leave that for you to think it through.