Two lighthouse
can be seen from the top of the hill the first flashes once every six seconds and the other flashes every once every 15 seconds is the flash how long is it until the first again at the same time

30 seconds

Step-by-step explanation:

suppose they flash together the first time at time t1

they will flash together again on the first multiple of t1 that is common to the two lighthouses which is 30

15*2=30

6*5 = 30

30 seconds.

Step-by-step explanation:

This will be equal to the lowest common multiple of 6 and 15.

6 = 2 * 3

15 = 3 * 5

The LCM = 2*3*5 = 30.

Answer : 30 seconds.

1

step-by-step explanation:

you are throwing one dart