Question

There is a star with three orbiting planets. One planet makes a trip around the star in 6 years. The second planet takes 9 years to make a trip around the star. The third planet takes 18 years to make the trip. How many years will it take for the planets to line up again?

Answer 1

Answer:

18

Step-by-step explanation:

The answer is simply the LCM of the years.

LCM of 6,9,18 = 18.

So the planets line up again after 18 years.

Answer 2

Answer:

It will take 18 years for the planets to line up

Step-by-step explanation:

You just find the least common multiple of the numbers

6 = {6, 12, 18, 24, 30, 36,...}

9 = {9, 18, 27, 36, ...}

18 = {18, 36,...}

HOPE THIS HELPS