Question

What is the probability of getting either blue or freen on a spinner that is 3/10 green and 1/5 blue?
I added 3 and 1 and got 4. So is my answer 4/10 ?

Answer 1

In reality, you need to be considering these:
green - 3/10
blue - 2/10

Do you see why?

Answer 2

because 5 times two is ten and 1 times 2 is 2 but you do this because you need a comen denominater