ExamBro
ExamBro
TS EAMCET · Maths · Probability

The probability of choosing randomly a number \(c\) from the set \(\{1,2,3, \ldots, 9\}\) such that the quadratic equation \(x^2+4 x+c=0\) has real roots is

  1. A \(\frac{1}{9}\)
  2. B \(\frac{2}{9}\)
  3. C \(\frac{3}{9}\)
  4. D \(\frac{4}{9}\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(\frac{4}{9}\)

Step-by-step Solution

Detailed explanation

Given, \(x^2+4 x+c=0\) For real roots, \(\begin{aligned} D & =b^2-4 a c \geq 0 \\ & =16-4 c \geq 0 \end{aligned}\) \(\Rightarrow \quad c=1,2,3,4\) will satisfy the above inequality. \(\therefore\) Required probability \(=\frac{4}{9}\)