probability that the number drawn is a multiple of 3

Navyguy

Junior Member
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Jul 24, 2006
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A number is drawn at random from the numbers 1 through 20. The probability the number is a multiple of 3 is:

1. 1/3
2. 1/5
3. 3/10
4. 7/20

Ok I ran this test here and I came up with number 3 after 5 random picks. So my answer is 1/5 is this right, thanks for checking.
 
Re: multiple of 3

Navyguy said:
A number is drawn at random from the numbers 1 through 20. The probability the number is a multiple of 3 is.
How many multiples of three are there?
 
Re: 6, 3s

Navyguy said:
we have 6 multiple 3s
So what is the probability a drawn number is a multiple of three?
 
6

I would say 6 times of random picking a number would be a multiple of 3. But that isn't an answer in my home work problem.

1. 1/3
2. 1/5
3. 3/10
d. 7/20, only one close is 7/20 if you count your first try at picking a random number.
 
Re: 6

Navyguy said:
I would say 6 times of random picking a number would be a multiple of 3. But that isn't an answer in my home work problem.

1. 1/3
2. 1/5
3. 3/10
d. 7/20, only one close is 7/20 if you count your first try at picking a random number.
6/20
 
thanks, but

Ok, I see what you did, but 3/10 is 3 out of 10 picks had a multiple of 3. I'm just trying to understand ok. It looks like you got upset when I did the equation wrong. Sorry if this is true. I know math comes easy for some and not so easy for others. and well I'm an other. lol.. thanks again for all your help and understanding.
 
Re: thanks, but

Navyguy said:
It looks like you got upset when I did the equation wrong. Sorry if this is true.
What in the world made you think that?
It does seem as if you are just guessing sometimes.
Glad that you are trying to understand and not just get an answer.

In this case, there are 6 multiples of 3 out of 20: 6/20.
The probability of drawing a multiple of 5 is 4/20. WHY?
 
multiple of 5 is 4/20. WHY?

hmmm good one, lets see. because of 5..5x4=20. Thats my answer but i'm sure i'm wong
 
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