Suppose that, in some distant part of the universe, there is a star with four orbiting planets . one planet makes a trip around the star in 6 earth years , the second planet takes 9 earth years, the third takes 15 earth years and the fourth takes 18 earth years . suppose that at some time the planets are lined up. how many years will it take for them to all line up

90 Earth years.

Step-by-step explanation:

Analizing the information provided in the exercise, you need to find the Least Common Multiple (LCM) of the given numbers.

You can follow these steps:

1. You must descompose 6, 9, 15 and 18 into their prime factors:

2. Finally, you need to choose the commons and non commons with their greatest exponents and multiply them. Then you get:

Therefore, it will take 90 Earth years for them to all line up.

this might get deleted, sorry. it has to be an actual question. if you really wanted to give someone free points, ask a question like "why does the sky look blue, and the sun is yellow to our eyes? "

step-by-step explanation:

step-by-step explanation: