# maths GCSE

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Thread starter 5 months ago
#1
Megan has two boxes.

There are x beads in box A.
7 of these beads are white.
The rest of the beads are black.

There are x beads in box B.
4 of these beads are white.
The rest of the beads are black.

She chooses at random a bead from box A.

She notes the colour and then places this bead into box B.

She then chooses at random a bead from box B.

The probability of choosing a white bead from box A and a white bead from box B is

Work out the total number of beads in the two boxes.
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5 months ago
#2
Send a pic of the question
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5 months ago
#3
What is the probability?
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5 months ago
#4
(Original post by 8013)
What is the probability?
Yh thats what I was thinking
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5 months ago
#5
(Original post by shaheryar9)
Megan has two boxes.

There are x beads in box A.
7 of these beads are white.
The rest of the beads are black.

There are x beads in box B.
4 of these beads are white.
The rest of the beads are black.

She chooses at random a bead from box A.

She notes the colour and then places this bead into box B.

She then chooses at random a bead from box B.

The probability of choosing a white bead from box A and a white bead from box B is

Work out the total number of beads in the two boxes.

Don't know if you've seen the other responses but there is some information missing from this question!

Can you upload a picture of the original?
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Thread starter 5 months ago
#6
13. Megan has two boxes.

There are x beads in box A.
7 of these beads are white.
The rest of the beads are black.

There are x beads in box B.
4 of these beads are white.
The rest of the beads are black.

She chooses at random a bead from box A.

She notes the colour and then places this bead into box B.

She then chooses at random a bead from box B.

The probability of choosing a white bead from box A and a white bead from box B is 7/22

Work out the total number of beads in the two boxes.
th
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5 months ago
#7
(Original post by shaheryar9)
13. Megan has two boxes.

There are x beads in box A.
7 of these beads are white.
The rest of the beads are black.

There are x beads in box B.
4 of these beads are white.
The rest of the beads are black.

She chooses at random a bead from box A.

She notes the colour and then places this bead into box B.

She then chooses at random a bead from box B.

The probability of choosing a white bead from box A and a white bead from box B is 7/22

Work out the total number of beads in the two boxes.
th
OK, so a good idea would be to try to draw some sort of probability tree so you can see what's going on and how you can get to the event of drawing white from A followed by white from B.

This will give you an equation which you can solve for x.
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