Question

Two light houses flash their lights every 40 seconds and 50 seconds respectively.
The lights flashed together at 7p.m.When will they next flash the lights together ?

Answer 1

Answer:

Step-by-step explanation:

If the two lights flashed at the same time then they will again flash together at the LCM of the time they take to flash once.

So, we have to find the LCM of 20 and 30.

20 = 2 × 2 × 5

30 = 2 × 3 × 5

LCM(20,30) = 2 × 5 × 3 × 2

LCM(20,30) = 60

Step-by-step explanation: