Questions 1, 2 and 3 are ok.
Question 4 :
I don't see any black marble :/a.) The first marble picked is black and the second is red: 5/36
Ok.b.) Obtaining 2 white marbles: 1/16
So far #1 and #2 are correct, but #3 has an error...
a) is correct3.) A red and a black die labelled 1 - 6 are thrown simultaneously, find the probability of:
a.) A number less than 5 on the red die: 2/3
b.) A number less than 5 on the red die but a totla of 10 altogether: 1/36
c.) Both die adding to 10: 1/12
given that, b) should be equal to
c) is correct, three possibilities out of thirty-six
a) 0, there are no black marbles4.) There is 3 white marbles, 4 blue marbles and 5 red marbles in a bag. Find the probabilty of if marbles are picked WITH REPLACEMENT:
a.) The first marble picked is black and the second is red: 5/36
b.) Obtaining 2 white marbles: 1/16
b) , Remember, the white marble is replaced by another white marble.
#5, #6 and #7 are all correct
Note: Best way to solve #7 is by using a Venn diagram
The probability to get a white marble is 3/12=1/4b) , Remember, the white marble is replaced by another white marble.
Since there is replacement, the probability to get 2 marbles will be the product of the probabilities of getting 1 marble, that is to say 1/4²=1/16, isn't it ?
Actually, 9/144 is 1/16...