Question

A box contains 8 red marbles, nine blue marbles and 11 yellow marbles. what is the probability that a marble chosen randomly from the box is blue? LEAVE ANSWER AS A FRACTION.

Answer 1

31%

Explanation:

the sum total of all marbles at the beginning is 8+(9+9)=26

the probability of picking a red marble at this point is p(1)=(8/26)

now 25 marbles remain, the distribution is now 8+17=25

the probability of picking a red marble at this point is p(2)=(8/25)

now 24 marbles remain, the distribution is now 8+16=24

the probability of picking a red marble at this point is p(3)=(8/24)

it follows that the remaining probabilities are for "not picking a red marble".

these probabilities are 1-p([1;2;3]).

Probabilities are multiplicative.

The probability for 3 consecutive non-red draws is then given by:

(1-8/26)*(1-8/25)*(1-8/24) = 103/325 | that's roughly 31%

not 100% sure!

Answer 2

9/28

Step-by-step explanation: you put the amout of blue marbles over the total marbels