Friday, November 13, 2009

Need help on independen and dependent events!!!!!?

here is the problem:u choose three objects at random without putting them back in.what is the probability that u get ..


1.a heart,a tree,an umbrella


2.none of the objects is a heart


3.the first object is a fork


*there are a total of 7 objects. 1 star,1 umbrella,1 heart,1 fork,1 tree,1 puzzle piece,1 clover*

Need help on independen and dependent events!!!!!?
1) Probability = (1/7) . (1/6) . (1/5) . 3!


1 out of 7 chance of object being a heart


1 out of remaining 6 chance of object being a tree


1 out of remaining 5 chance of object being an umbrella


Then we permutate 3 objects





2) Probability = (6/7) . (5/6) . (4/5)


6 out of 7 chance of object not being a heart


5 out of remaining 6 chance of object not being a heart


4 out of remaining 6 chance of object not being a heart





3) Probability = 1/7


We do not worry about objects 2 and 3 at all


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