Gallery Problems Exercise

Fourth Rock

Work Time

Fourth Rock

The planet Zantron is an imaginary planet that is a lot like Earth. It is the third planet from its sun. Its year—the time it takes the planet to go around the sun—is exactly 12 months.

Zort—the fourth planet in that solar system—takes exactly 20 months.

Scientists on Zantron want to communicate with the colony on Zort, but their radio only works when the planets are aligned so that they are at the closest distance possible from each other.

  1. If the two planets are at their closest point now, how many months will it be before they are at their closest point again?
  2. Explain the math you used to get your answer.