Probability question: picking colored marbles out of a bag

[Rubies]

Homework Statement

there are 5 marbles in a bag: 4 are blue, and 1 is red. What is the probability that a blue marble gets picked?

Relevant Equations

.

there are 5 marbles in a bag: 4 are blue, and 1 is red.
Solution there are 5 in total 4 are Blue so 4/5 or80%
Is it right?
thanks

 

[member 587159]

Yes, it is correct.

 

[LCKurtz]

Except you should express it as $\frac 4 5 = .8$, not $80$% as probabilities are $0\le p \le 1$.

 

[SammyS]

Problem Statement: there are 5 marbles in a bag: 4 are blue, and 1 is red. What is the probability that a blue marble gets picked?
Relevant Equations: .

there are 5 marbles in a bag: 4 are blue, and 1 is red.
Solution there are 5 in total 4 are Blue so 4/5 or80%
Is it right?
thanks

Hello Rubies .

 

[member 587159]

Except you should express it as $\frac 4 5 = .8$, not $80$% as probabilities are $0\le p \le 1$.

80% = 80/100 = 4/5, not entirely sure what you are debating here.

 

[Mark44]

80% = 80/100 = 4/5, not entirely sure what you are debating here.

He's saying that the question asked for a probability, which is a number in the interval [0, 1].

 

[member 587159]

He's saying that the question asked for a probability, which is a number in the interval [0, 1].

And 80% is just a convenient way to say $80/100$, which is such a number. It really doesn't matter.

 

[LCKurtz]

And 80% is just a convenient way to say $80/100$, which is such a number. It really doesn't matter.

In the big scheme of things, you're right. It doesn't matter. The OP clearly understands how to do the problem. But this is a math forum and, in mathematical thought, precision matters. If that had been a 10 point problem on a test, I would have awarded 9 points. 80 is not a number on [0,1].

 

[member 587159]

In the big scheme of things, you're right. It doesn't matter. The OP clearly understands how to do the problem. But this is a math forum and, in mathematical thought, precision matters. If that had been a 10 point problem on a test, I would have awarded 9 points. 80 is not a number on [0,1].

But the OP said $80$%, which is not 80, but $80/100 \in [0,1]$. I would give the OP full marks if this was a test question. I think substracting points for things like that is the reason that people will get to hate math.

 

[SammyS]

C'mon guys. We know the point of view of each of you.

 

[Mark44]

But the OP said $80%$

I can see that you wrote 80%, but when your LaTeX gets rendered, it eats the % character.

 

[member 587159]

I can see that you wrote 80%, but when your LaTeX gets rendered, it eats the % character.

Edited.