I need some help with some probability questions

  • Thread starter sneaky666
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    Probability
In summary, the probability of choosing all 6 red balls from two pots with a total of 26 balls, given that all balls are the same color, is 2/79. And the probability of getting 2 jacks from a hand of 7 cards, followed by a roll of 3 on a die, is 1/49.
  • #1
sneaky666
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Homework Statement


1.
In two pots, pot1 has 5 red balls, and 7 blue balls and pot2 has 6 red balls and 12 blue balls.
3 balls are chosen from each pot.
What is the probability that all 6 are red conditional on the fact that all are the same color?
2.
Someone rolls a die and then picks cards from a standard deck equal to the number showing on the die.
a) What is the probability that the number of jacks in the hand equals 2?
b) Conditional on knowing the number of jacks in the hand equals 2, what is the conditional probability that the die showed 3?

Homework Equations





The Attempt at a Solution


1.
A = probability of all same color
B = probability of all red
C = probability of all blue
all combinations for pot1 = 12x11x10 / 3x2x1 = 220
all combinations for pot1 = 18x17x16 / 3x2x1 = 816
all combinations for both pots = 220x816 = 179520
A = B u C
P(A) = P(B) + P(C) - 0
P(B) = (5choose3)(7choose0)(6choose3)(12choose0) / 179520 = 5/4488
P(C) = (5choose0)(7choose3)(6choose0)(12choose3) / 179520 = 35/816
P(A) = 5/4488 + 35/816
P(A) = 395/8976
P(all red|all same color) = P(all red ^ all same color) / P(all same color)
= (5/4488) / (395/8976) = 2/79

2.
 
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  • #2
a) P(2 jacks) = (4choose2)(48choose5) / 52choose7 = 0.00185897b) P(3|2 jacks) = (4choose2)(48choose5) / (4choose2)(49choose5) = 1/49
 

1. What is probability and how is it used?

Probability is the measure of how likely an event is to occur. It is used in various fields such as mathematics, statistics, and science to make predictions and analyze data.

2. How do I calculate probability?

To calculate probability, you divide the number of favorable outcomes by the total number of possible outcomes. This can be represented as P(A) = Number of favorable outcomes / Total number of possible outcomes.

3. What is the difference between theoretical and experimental probability?

Theoretical probability is based on mathematical calculations and assumes that all outcomes are equally likely. Experimental probability is based on actual data collected from experiments or observations.

4. Can probability be greater than 1 or less than 0?

No, probability cannot be greater than 1 or less than 0. It is always expressed as a number between 0 and 1, where 0 represents an impossible event and 1 represents a certain event.

5. How can I use probability in real life scenarios?

Probability can be used in real life scenarios to make informed decisions and predictions. For example, it can be used in weather forecasting, stock market analysis, and risk assessment in insurance. It can also be used to understand and interpret data in various fields of research.

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