Practice china-kaoyan-math-3 questions with answers and explanations.
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Use the circle-area formula A = πr². Substituting r = 6 gives A = π × 6² = 36π.
Percentage=(13/28)×100=46.43.
Subtract 9 from both sides and divide by 8: x = (41-9)/8 = 4.
By Vieta’s formula, the sum of the roots equals the coefficient 13.
aₙ=a₁+(n−1)d=8+(14−1)×4=60.
Percentage=(12/27)×100=44.44.
Subtract 8 from both sides and divide by 7: x = (29-8)/7 = 3.
By Vieta’s formula, the sum of the roots equals the coefficient 10.
aₙ=a₁+(n−1)d=7+(13−1)×3=43.
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The sum is n(n+1)/2=45, so the mean is 45/9.
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There are 5 favourable outcomes out of 10 equally likely outcomes, so P(red)=5/10.
The coordinate differences are 3 and 4, so the distance is √(3²+4²)=5.
