coolhabhi wrote:paridhi wrote:Three balls aee drawn (w/o replacement) from an urn containing 5 Blue balls, 4 Green balls and 3 yellow balls. What is the probability of drawing a blue ball, green ball and a yellow ball in that order?
A. 1/220
B. 1/60
C. 5/144
D. 1/22
E. 47/60
OA is D
Can someone please explain....
Why isnt the answer : (5C1 * 4C1 * 3C1)/12C3 ??
Experts please help..
I'm certainly no expert, but here goes...
Remember this RULE:
To determine the probability that event X AND event Y will both occur, MULTIPLY the two probabilities together.
What is the probability of each event happening without replacement?
Well, probability= number of successful outcomes/total number of possible outcomes.
There are a TOTAL number of 12 balls.
1) blue ball: 5/12
There are 5 blue balls (therefore 5 chances of picking one of them) and 12 total balls.
2) green: 4/11
There are now a pool of 11 balls because we had already taken one out of the original pool of balls
3) yellow: 3/10
Multiplying these together... 5/12*4/11*3/10=1/22
Notice that it doesn't matter what order you pick the balls in. Your outcome will still be the same
For example: yellow green blue
3/12*4*11*5/10=1/22
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