Question

In an industrial area, three factories give out sirens at an interval of 40 minutes, 1 hour and one and a half hour, respectively. Find the time between two simultaneous sounds of three sirens.​

Answer 1

Answer:

6 hours.

Step-by-step explanation:

That would be the Lowest Common Multiple of  40, 60 and 90 minutes.

40 = 2*2*2*5

60 = 2*2*3*5

90 = 2*3*3*5

The LCM = 2* 2 * 2 * 3 *3 * 5

= 8 * 9 * 5

= 360.

So the answer is 360 minutes or 6 hours.