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## #1 2006-07-27 02:20:16

Devantè
Real Member

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### Basic Probability

Basic Probability Excercises

Basic probability, as the title states. There are quite fun to do. Have fun!

1. Two dice are rolled. The events 'obtaining a six with the first die' and 'obtaining an even number with the second die' are independent. True or False?
2. A box contains 7 red balls and 4 white balls. Two balls are taken out and not replaced. The events 'the first ball is red' and 'the second ball is white' are independent. True or False?
3. A bag contains 3 green counters and 6 black counters. A counter is taken from the bag, its colour noted, and then replaced. A second counter is then taken from the bag. The events 'the first counter is green' and 'the second counter is black' are independent. True or False?

A bag contains 2 red beads and 3 black beads. Two beads are taken from the bag without replacement.

4. P = ?
5. Q = ?
6. R = ?
7. S = ?
8. What is the probability that both beads are the same colour?
9. What is the probability of obtaining exactly one red bead?
10. What is the probability of obtaining at least one red bead?
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Last edited by Devanté (2006-07-27 02:20:57)

## #2 2009-05-25 04:15:24

bobbym

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### Re: Basic Probability

An oldie but goody

#1 True

#2 False

#4 .25

#5 .75

#6 .5

#7 .5

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

## #3 2009-05-29 11:44:20

Fruityloop
Full Member

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### Re: Basic Probability

1.    True
2.    False
3.    True
4.    .1
5.    .3
6.    .3
7.    .3
8.    .4
9.    .6
10.   .7

The eclipses from Algol (an eclipsing binary star) come further apart in time when the Earth is moving away from Algol and closer together in time when the Earth is moving towards Algol, thereby proving that the speed of light is variable and that Einstein's Special Theory of Relativity is wrong.

## #4 2009-05-29 17:19:52

bobbym

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### Re: Basic Probability

Hi fruityloop;

#4 .1                   Yes! careless arithmetic error on my part!

#5 .3                   Yes again! Same lame excuse as above!

#6 and #7 .3        Even more apologies!

Forgot to multiply by the first branch of the tree! Thanks for catching the errors.

Last edited by bobbym (2009-05-30 09:53:08)

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.