Numeracy question?

A pack contains five cards each showing one letter: A, B, C, D, E.
The cards are shuffled and one card is drawn at random. The letter on it is noted and the card replaced.
A second card is then drawn and the letter noted.
What is the probability that the card with the letter B is chosen at least once?
Give your answer as a fraction in its simplest form.

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Mamapolo2016 · F

If the exposed card goes back into the deck, the probability of the next card being B at least once stays the same.

Each draw, probability is 20% or one in five. 1/5.

I think.

summerlove · 31-35, F

@Mamapolo2016 The answer is 9/25. They're practice questions and not sure how where the 9 part comes from.

OggggO · 36-40, M

@summerlove Each draw has independent 1/5 or 5/25 chance of turning up a specific result. Multiple draws increase the chance, but at a diminishing rate. I don't know the exact formula, but basically, the longer you do it, the more likely it is that you will turn up that result at least once, but it's never completely guaranteed.

Think of a simpler version: flipping a coin. There are only two outcomes, heads and tails. Flip it once, and you have a 50/50 shot of getting a heads. Flip it three times, and you've probably gotten at least one heads, but it's not unheard of to go three tails in a row. Flip it ten times and you have almost certainly gotten at least one heads, but one can never say for sure. Flip it one hundred times, and it's extremely unlikely, but not completely impossible, to have gotten no heads. Etc.

Msp940 · 41-45, M

1/20 but this is a terrible place to get math advice. This answer assumes the first card is returned to the deck.

sighmeupforthat · 46-50, M

NO!

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summerlove · 31-35, F

@Psycho Where does the 9 come from? That's what has me confused.

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