Question
A bag contains 9 white balls, 6 black balls, and 3 green
balls. Two balls are drawn at random. Find the probability that the two balls are white.Solution
Number of ways of selecting two white balls = 9Câ‚‚
Total number of balls = 9 + 6 + 3 = 18
Number of ways of selecting two balls = 18 Câ‚‚
Probability = 9 C₂ ÷ 18 C₂ = (9 × 8) ÷ (18 × 17) = 72 ÷ 306 = 4/17
I. y² - 7 y – 18 = 0
II. x² + 10 x + 16 = 0
I. 2x² - 11x + 12 = 0
II. 12y² + 29y + 15 = 0
I. 40x² + 81x + 35 = 0
II. 63y² + 103y + 42 = 0
I. 3p² - 11p + 10 = 0
II. 2q² + 13q + 21 = 0
I. 2x2 – 19x + 45 = 0
II. y2 – 14y + 48 = 0
If the roots of the quadratic equation 6m² + 7m + 8 = 0 are α and β, then what is the value of [(1/α) + (1/β)]?
 If x satisfies x² – 14x + 40 = 0, find x.
I. 81x - 117√x + 40 = 0
II. 81y - 225√y + 136 = 0
If the roots of the quadratic equation 5x² + 4x + 6 = 0 are α and β, then what is the value of [(1/α) + (1/β)]?
...I. 4x² - 21 x + 20 = 0
II. 8y² - 22 y + 15 = 0
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