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# OCR S1 Exam Question Help! (Rep+) watch

1. Hey guys,

I am in need of some help!

Paul plays a game in which a fair coin is spun 4x. If the number of heads is 0 or 1, Paul looses £5, if the number of heads is 2, Paul wins £5 and if the number of heads is 3 or 4, Paul wins £10. Let £W be the amount for which he wins one random game.

i) Show that P(W=-5)=5/16
ii) work out P(W=5)

So for i) there are 5 possible choices if you draw tree diagram, so 5(1/2)^4 would get me 5/16

ii) I am stuck here... if you can have (HHTT) this can be arranged in 4!/2! ways which is 12 ways that can be arranged... so would it therefore be 12(1/2)^4 which is 3/4?
2. Bump!

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Updated: March 23, 2011
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