Question

Let ‘head’ means one and ‘tial’ means two and the coefficients of the equation $a{x}^2+bx+c=0$ are chosen by tossing a coin. The probability that the roots of the equation are non – real, is equal to:

• A. $\frac{5}{8}$
• B. $\frac{7}{8}$
• C. $\frac{3}{8}$
• D. $\frac{1}{8}$

Answer 1

The correct option is B $\frac{7}{8}$

a, b, c may be 1 or 2.
$a{x}^2+bx+c=0$ has non - real roots if $D=b^2-4ac<0$.

Hence probability =$\frac{7}{2^3}=\frac{7}{8}$