Answer:
Green: (2/11) * (1/10)
Yellow: (2/5) * (1/3)
Purple: (3/10) * (6/19)
Blue: (1/4) * (13/51)
Explanation:
Green:
>> Maria has 11 letters in her bag, and 2 of them are B's.
>> At first, the chance of drawing a B is 2 out of 11: 2/11.
>> Let's assume that everything goes according to plan, and she actually draws a B.
>> Then she has 10 letters, and only one of them is B (she already has the other one).
>> That means that the chance of drawing that B is 1 out of 10: 1/10.
>> Thus, (2/11)*(1/10).
Yellow:
>> There are 11 + 13 + 16 = 40 items in the closet.
>> The probability of selecting a prop is 16/40 = 2/5 (there are 16 props and 40 items).
>> That means that there are 40-1=39 items left.
>> Therefore, the probability of selecting a costume is 13/39 = 1/3 (as there are 13 costumes and 39 items).
>> The answer is (2/5) * (1/3).
Purple:
>> There are 6+8+6=20 jellybeans.
>> At first, Hannah grabs an orange candy (there are 6 of them): 6/20 = 3/10.
>> Then there are 19 candies left.
>> Then she grabs a pink one (there are 6 of them): 6/19.
>> The answer is (3/10)*(6/19).
Blue:
>> There are 52 cards in a standard deck, 13 clubs, 13 spades, 13 hearts, 13 diamonds.
>> The 1st is a spade: 13/52 = 1/4.
>> There are 51 cards left.
>> The 2nd is a club: 13/51.
>> (1/4)*(13/51).