Arihant Gate tutor 2014

Question

The traffic lights at three different road crossings change after every 50s,75s and 100s respectively.If they start changing simultaneously at 10 am,after how much time will they change again simultaneously?(Ans:-5min)

Answer 1

For such questions, take LCM of all the numbers.

For this problem, it comes out to be 300(s) i.e. 5 minutes.

So, 300 seconds is the least interval after which they will change simultaneously; and they will continue to change simultaneously in the interval of multiples of 300 seconds(5 minutes).