A spaceship landed on Earth.

There were 200 aliens on board the spaceship.

40% of them were green aliens and the rest were red aliens.

Some red aliens left the spaceship and stayed behind on Earth.

Subsequently, the number of red aliens on board the spaceship reduced to 20% of the total number of aliens on board the spaceship.

(a) How many green aliens were on board ?

(b) Find the total number of aliens on board the spaceship after it left Earth?

Notes to students:

1. If the question above has parts, (e.g. (a) and (b)), given that the answer for part (a) is 10 and the answer for part (b) is 12, give your answer as:10,12