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32 votes
32 votes
NEED HELP ASAP!!!!!!!!!

Steve has 12 biscuits in a tin.
There are 7 digestive, 2 chocolate and 3 ginger biscuits.
Steve takes two biscuits at random from the tin.
Work out the probability that he chooses two different types of biscuits.

User Martin Gallagher
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2 Answers

15 votes
15 votes

Answer:

There are two patterns to chose two different biscuits; a digestive then a chocolate or a chocolate and then a digestive.

The probability of choosing a digestive then a chocolate is as follows:

7/12 * 5/11 =0.265

The probability of choosing a chocolate then a digestive is as follows:

5/12*7/11 = 0.265

Therefore the combined probability is 0.53 or 53%

User Velimir
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3.5k points
28 votes
28 votes

Probability of digestive and chocolate

  • 7/12×2/11=14/132=7/66

And

  • 2/12×7/11=7/66

Probability of digestive and ginger

  • 7/12×3/11=21/132=7/44

And

  • 3/12×7/11=7/44

Probability of ginger and chocolate

  • 2/12×3/11=6/132=3/66=1/22

User Stanlekub
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3.0k points