Please give me a couple of minutes, I’ll answer in the comment section
15, 20, 25 is the correct answer
So you can say that the weight of a koala here can be x.
So x * 1/8 = 2
2 being the chinchilla's weight and the 1/8 coming from the fact that the chinchilla weighs 1/8 of the weight of the koala.
So you can just divide both sides by 1/8 first.
x * 1/8 = 2
/ 1/8 / 1/8
Or,
x *1/8 * 8/1 = 2 * 8/1
x = 16
So the koala weighs 16 pounds.
2 balls fell because he dropped 2
That would be 1/2 * the base = 21 * 1/2 = 10.5 in.