Question

Barbara draws pens randomly from a box containing 5 pens of the same shape and size. There is 1 green pen, 3 red pens, and 1 blue pen. She draws 1 red pen and then another red pen without replacing the first one. Find the probability of drawing 1 red pen followed by another red pen, and show the equation used.

Answer 1

Let total number of pens = N pens (green+ red+ blue)

Let number of red pens = n red pens

Probability of drawing one red pen = n/N

Probability of drawing one red pen followed by another red pen (witnout replacement)

\[\frac{ n }{ N } * \frac{ ( n-1) }{ (N-1) }\]

Answer 2

what do I do now.

Answer 3

You know n and N
You can calculate the probability

Answer 4

can you do that for me?

Answer 5

Have a try?

Answer 6

Ok.

Answer 7

So we add all the number of pens and that equals= 5.

Answer 8

ok and that is N

Answer 9

Yes

Answer 10

and for the number of red pens that is 1/5.

Answer 11

How many red pens are there?

Answer 12

one.

Answer 13

No, you draw one red pen

Answer 14

There's a total of two

Answer 15

Since there's a another one.

Answer 16

no, look at the second line

Answer 17

its three red pens

Answer 18

I see it now.

Answer 19

what's the probability?

Answer 20

3/5

Answer 21

That's the probanility of drawing the first red pen, then how many pens are left?

Answer 22

if you take one out.

Answer 23

yes

Answer 24

Two.

Answer 25

two red pens
And the total pens left are....

Answer 26

five

Answer 27

no, you have taken one (without replacement)

Answer 28

four.

Answer 29

ok, then the probability of getting the second red pen is

Answer 30

3/4

Answer 31

no

Answer 32

2/4

Answer 33

yes, Then you have the probability of drawing the first red pen and the probability of drawing the second red pen, what do you do next?

Answer 34

Multiply

Answer 35

yes

Answer 36

3/4x2/4=6/16

Answer 37

I think

Answer 38

the first one is 3/5
and the second is 2/4

Answer 39

3/5x2/4=6/20

Answer 40

yes, you can simplify by dividing numerator and denominator by 2

Answer 41

as a another way.

Answer 42

no, simplify the final result

Answer 43

1/3x1/2=1/6

Answer 44

3/5 *2/4=3/5*1/2= ?

Answer 45

1

Answer 46

\[\frac{ 3 }{ 5 } * \frac{ 1 }{ 2 }=\]

Answer 47

4/10

Answer 48

no

Answer 49

3/10

Answer 50

yes, that's the answer

Answer 51

Thank you.

Answer 52

You are welcome