A bag contains 6 one-dollar coins and 4 two-dollar coins. Three coins are taken at random without replacement.
1 answer:
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<h3>Answer: 5</h3>
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Explanation:
Apply the difference of squares rule
x^2 - y^2 = (x-y)(x+y)
x^2 - y^2 = (5)(1)
x^2 - y^2 = 5
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Alternatively, you can solve the system
for x and y to get (x,y) = (3,-2).
Then compute x^2-y^2 = 3^2-(-2)^2 = 9-4 = 5