so does this mean she has a 2/5 chance of 1st or 2nd try, or does this not include every possibility

i also thought it could be 4/25, but probability is brand new to me and i am not sure which way would be correct???????????

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so does this mean she has a 2/5 chance of 1st or 2nd try, or does this not include every possibility

i also thought it could be 4/25, but probability is brand new to me and i am not sure which way would be correct???????????

The a probability of \(\displaystyle \left(\frac{3}{5}\right)\left(\frac{2}{5}\right)\) of opening it on the second try. WHY?

SO WHAT?

1st 2nd

Plato,

I understand:

She has a probability of opening on the first try.

I do not understand why she has

The a probability of of opening it on the second try. WHY?

Well it depends upon how one reads the problem.

1st 2nd

Plato,

I understand:

She has a probability of opening on the first try.

I do not understand why she has

The a probability of of opening it on the second try. WHY?

It says that she cannot see the keys.

So I assume that she could try the same key again.

That may not be a correct understanding.

You seem to read it as if she would not try the same key twice.

I don't which is correct.

why did you say that he had a 2/5 chance on the first then a (3/5)(2/5) chance on the second try...this i do not understand?

Then, second, if he keeps the first key he tries separated from the other keys, he would have a 2/5 chance on the first try and a 2/4 chance on the second try for a probability of 4/20...correct?

sorry, this stuff is new to me, thanks for helping

Because he must have failed on the first try.why did you say that he had a 2/5 chance on the first then a (3/5)(2/5) chance on the second try...this i do not understand?

The probability of failure is (3/5).

The probability of

He fails twice and then succeeds.

The question to answer is: What is the probability she will get it open on the first or second try?

Okay, so first, let us say he cannot see the keys, then he would have a 2/5 chance on the first try and a 2/5 chance on the second try for a probability of 4/25...correct?

Then, second, if he keeps the first key he tries separated from the other keys, he would have a 2/5 chance on the first try and a 2/4 chance on the second try for a probability of 4/20...correct?

So is my thinking way off?

The probability that she opens the door on her first or second try is:

\(\displaystyle \frac{2}{5}+\left(\frac{3}{5}\right) \left(\frac{2}{5}\right) \).

Now assume that she

The probability that she opens the door on her first or second try is:

\(\displaystyle \frac{2}{5}+\left(\frac{3}{5}\right) \left(\frac{2}{4}\right) \).