Androids and Boods Question?

Question

Androids and Boods have landed on Mars. Androids have green skin and Boods have 5 arms. 87% of all Androids are Boods. 3% of all Boods are Androids. There are 13 Androids that are not Boods. How many Boods are not Androids?

Please can you explain - you probably have to be real clever to get this, I'm not that good. Thanks everyone.

Answer 1

If 87% of androids are boods, and 13 androids are not boods, then that means 13 is 13% of the number of androids (100), of which 87 (87%) are boods. This is 3% of the bood population, so the total number of boods is 87/.03 = 2900. 2900 - 87 means 2813 boods are not androids.