a) There is 20 marbles Total, 6 Yellow. The p(3 yellow) =
6/20 * 5/19 * 4/18 = 1/57
Or
(6 C 3)/(20 C 3)
To explain this, you have 6 yellow marbles and 20 total. So 1st pick is prob of 6/20. Now there is 5 yellow marbles left and 19 total. So the prob to pick a 2nd yellow marble is 5/19. Now there is only 4 yellow marbles left and 18 total marbles. Last pick then is 4/18.
b)
5/20 * 2/19 * 1/18 = 1/684
or
(5 C 1)*(2 C 2)/(20 C 3)
A bag of marbles contains 5 brown, 6 yellow, 4 blue, 3 green and 2 orange.
What is the probability of:
a) getting 3 yellow marbles, if 3 are taken at a time?
b) getting 1 brown and 2 orange marbles, if 3 are taken at a time?
a= 6/20* 5/19* 4/18
b=5/20* 2/19* 1/18
1 answer
1 answer