Pita has 12 coins in her bag. There are three £1 coins and nine 50p coins. She takes 3 coins from the bag at random.

Question

Pita has 12 coins in her bag.
There are three £1 coins and nine 50p coins.

She takes 3 coins from the bag at random.

work out the probability that she takes exactly £2.50

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Harper 3 weeks 2021-11-08T23:05:51+00:00 1 Answer 0 views 0

Answers ( )

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    2021-11-08T23:07:26+00:00

    Answer:27/220

    Step-by-step explanation:

    She must have 2 �1 coins and 1 50p coin.

    She can choose the 2 �1 coins 3C2 = 3 ways.

    For each of those 3 ways she can choose the

    50p coin 9C1 or 9 ways.

    That’s 3�9=27 ways to get �2.50.

    She can choose any 3 coins in 12C3 = 220 ways.

    The desired probability is 27 ways out of

    220 ways,or 27/220, or 13.5% of the time.

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