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anonymous
 5 years ago
The probability of randomly selecting a red marble from a bag, replacing it, and selecting a red marble again is 1/25.
What is the probability of selecting a red marble on the first try?
anonymous
 5 years ago
The probability of randomly selecting a red marble from a bag, replacing it, and selecting a red marble again is 1/25. What is the probability of selecting a red marble on the first try?

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anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0I will become your fan and give you a medal for the right answer

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0reason: same number of marbles in the bag the second time as the first. same number of red marbles the second time as well. so nothing has changed and the probabilities are the same.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0oh wait. i need to read the question more carefully. hold on.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0hold on i think i was mistaken. sorry.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0i misread. let me try again and this time go slow, and maybe with an explanation.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0put A = the event you select a red marble on the first try. we want \[P(A)\] B = event you select a red marble on second try.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0\[A\cap B\] is the even that both marbles selected were red, and you are given that \[P(A\cap B)=\frac{1}{25}\] because you are given that the probability that both marbles selected were red

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0in general \[P(A\cap B) = P(A)\times P(BA)\] but since you have replaced the red marble there are the same number of red marble in the bag and the same number of marbles, so \[P(B)=P(A)\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Shouldn't it be 1/5. 1/5 * 1/5 = 1/25 th

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0therefore you have \[\frac{1}{25}=P(A)\times P(A)\] so \[P(A)=\frac{1}{5}\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0That is the probability of selecting it once into the same probability of it being picked again

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0yes you are right isan_meswani. my first answer was a mistake. i read the problem incorrectly.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0sorry i messed you up on first try.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Suppose you know there are originally 2 red marbles in the bag. How many marbles are there in all?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Now this is simple, isn't it? its 10

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0yes that was an easy one. \[\frac{1}{5}=\frac{2}{x}\]
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