Question 206307
There are 38 twenty cent coins, x ten cent coins and (2x-15)fifty cent coins in a box. A coin is selected at random and the probability that it is fifty cent coins is 1/8. Find the value of x. Hence, find the probability that the selected coin is a
(a) Twenty cent coin,
P(50 cent coin) = (2x-15)/[38+x+2x-15] = 1/8
Solve for "x":
8(2x-15) = 23+3x
16x-120 = 23+3x
13x = 143
x = 11
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So, P(20 cent coin) = 38/[38+x+2x-15] = 38/[38+11+22-15] = 38/56
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(b) Ten cent coin.
And, P(10 cent coin) = 11/56
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Cheers,
Stan H.