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Probability Question

There are only green pens and blue pens in a box

There are three more blue pens than green pens in the box.
There are more than 12 pens in the box.

Simon is going to take at random two pens from the box

The probability that Simon will take two pens of the same colour is 27/55


Work Out the number of green pens in the box.

Thanks in advance for any responses.
Original post by InfinityMist
There are only green pens and blue pens in a box

There are three more blue pens than green pens in the box.
There are more than 12 pens in the box.

Simon is going to take at random two pens from the box

The probability that Simon will take two pens of the same colour is 27/55


Work Out the number of green pens in the box.

Thanks in advance for any responses.

Have popped your thread into Maths, science and technology academic help :yy:
Would help but I feel there are more capable people around to help :colondollar:
:bump:
Reply 2
Avatar for SDrew33
SDrew33
10
So we know that the bottom of the fraction is 55. this could have been a multiple of this simplified.

we know that the denominator comes from the total times one minus the total if you draw the tree diagram for this.

55 can be split into 11 and 5. we need to find two numbers that are multiples of these with a different of 1. they are 44 and 45

so the total is 45

we then know that b=g+3 as three more blue than green

so 2g+3=total=45

therefore g is 21, testing this on calculator with g=21 and b=24 gives the probability of 27/55

hope this helps
Original post by InfinityMist
There are only green pens and blue pens in a box

There are three more blue pens than green pens in the box.
There are more than 12 pens in the box.

Simon is going to take at random two pens from the box

The probability that Simon will take two pens of the same colour is 27/55


Work Out the number of green pens in the box.

Thanks in advance for any responses.


The answer is 21 btw where did you get this question

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