Question

Lighthouse A sounds a foghorn every 4 hours, and Lighthouse B sounds a foghorn every 10 hours.

If both lighthouses sound their foghorns at the same time, how many hours will it be until the next instance when both foghorns sound at the same time?

14 hours

20 hours

24 hours

40 hours

Answer 1

Your answer is B 20 hours

Answer 2

20 Hours

Step-by-step explanation: If A sounds every 4 hours this means that after 4 times it sounds it will be at 20 hours and if B sounds every 10 hours this means it will sound twice before it also sounds at 20 hours.