Question

Find the probability of the given event. a bag contains 5 red marbles, 4 blue marbles, and 1 green marble. a randomly drawn marble is not blue.

Answer 1

The probability of an even is how likelihood this even happens.

For drawing a marble which has blue colour = $\frac{number~ of ~blue~ marbles}{all~ marbles'~number}= \frac{4}{5+1+4}= \frac{4}{10}=0.4$

After that, we are going to find the propability of the complementary event of drawing a blue marble, which could be calculated by this formula

$P(not~ blue) = 1 - P(blue)$

Apply it now....
P(not blue) = 1 - 0.4 = 0.6

I hope you got the idea!

I am with you if you faced any difficulties!

Answer 2

n(S) = 5 + 4 + 1 = 10 All marbles - The total no.of outcomes

n(E) = 4 Blue marble - The favorable outcomes 

$P(E)=\frac{n(E)}{n(S)}$ Formula

$P(E)=\frac{4}{10}=\frac{2}{5}$

Answer: 2/5 or 0,4 or 40%