# Maths Probability Homework

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Thread starter 9 months ago
#1
Finn has two bags of counters.
He takes a counter at random from each bag.
The probability that he takes a red counter from the first bag is 0.3.
The probability that he takes a red counter from the second bag is 0.4.
What is the probability that he takes at least one red counter?
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Thread starter 9 months ago
#2
Do you add the two probabilities, 0.3+0.4
or multiply them? 0.3x0.4
Just need the clarification. Thanks.
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9 months ago
#3
(Original post by fdrdferwfewrf)
Do you add the two probabilities, 0.3+0.4
or multiply them? 0.3x0.4
Just need the clarification. Thanks.
Neither.
At least one red counter means not both not red
So not (not red in bag 1 and not red in bag 2)
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9 months ago
#4
Try to solve this homework by a tree diagramm. There are to bags with red counters.

Bag 1 has a propability of p = 0.3 for red counter. What is the complementary propability? it is q = 1-p.

Bag 2 has p = 0.4. Complememtary propability?

As there are two bags, the tree diagramm can be drawn as a two-tiered try.

How many possibilities exist in total? how many of them have one red counter or more? count them!
Last edited by Kallisto; 9 months ago
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