Practice China questions with answers and explanations.
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There are 6 favourable outcomes out of 14 equally likely outcomes, so P(red)=6/14.
Rewrite the value using base 2: 4 = 2^2. Matching exponents gives x = 2.
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Use the circle-area formula A = πr². Substituting r = 6 gives A = π × 6² = 36π.
The dot product is 1×3+5×5=28.
Percentage=(12/47)×100=25.53.
Subtract 4 from both sides and divide by 2: x = (18-4)/2 = 7.
By Vieta’s formula, the sum of the roots equals the coefficient 11.
aₙ=a₁+(n−1)d=3+(9−1)×5=43.
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The sum is n(n+1)/2=10, so the mean is 10/4.
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There are 5 favourable outcomes out of 12 equally likely outcomes, so P(red)=5/12.
The coordinate differences are 3 and 4, so the distance is √(3²+4²)=5.
f′(x)=12x²+4x. Substituting x=1 gives 16.
