Bmat 2018-maths question 8

My wallet contains two 50p coins and five 20p coins only.

I need 70p to buy an item.

If I pick two coins at random from my wallet, what is the probability that I have picked the exact money to buy the item?

10/21 is the answer but i dont know how

hello!
could you include the answer of the question?

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Hi
isn’t the answer 10/21?

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IMG_0579

  1. picking 50p, then 20p
    = 2/7 * 5/6 = 5/21

  2. picking 20p, then 50p
    = 2/7 * 5/6 = 5/21

  3. Total p = 5/21 + 5/21 = 10/21, (C)

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yes it is, i included it in the original post