Question

Three light houses flash their lights every 16 second, 24 second and 40 seconds respectively. If they flash together at 2 p.m at what time will they next flash together?

Answer 1

We should take LCM of 16,24 and 40 seconds and add it with the given time i.e,2 pm  LCM of 16,24,40 is 240 which is 4 minutes   So they will flash together again at 2.04 pm  Hope it helps!

Answer 2

Answer :

They required 240 sec or 4 minutes.

Step-by-step explanation :

Given that :

16 seconds , 24 seconds and 40 seconds.

To Find :

Time

Solution :

We can tell the required time by finding the L.C.M of 16, 14 and 40.

$\begin{array}{r|l} 2 & 16,24,40 \\ \cline{1-2} 2 & 8,12,20 \\\cline{1-2} 2 & 4,6,10\\\cline{1-2} 2 & 2,3,5 \\\cline{1-2} 3 & 1,3,5 \\\cline{1-2} 5 & 1,1,5\\\cline{1-2}&1\end{array}$

LCM = 2 × 2 × 2 × 2 × 3 × 5

=> 240.

Thus,

The required time is 240 sec or 4 minutes.

Thus, the flash together as 2 : 04 pm secs.