Question

In an experiment, positive and negative value are equally likely to occur. The probability of obtaining at most one negative value in five trials is

• A. $\frac{1}{32}$
• B. $\frac{2}{32}$
• C. $\frac{3}{32}$
• D. $\frac{6}{32}$

Answer 1

The correct option is D $\frac{6}{32}$

$p=q=\frac{1}{2}$

Required probability
${=}^5{C}_0{\left(\frac{1}{2}\right)}^0{\left(\frac{1}{2}\right)}^5+{}^5{C}_1{\left(\frac{1}{2}\right)}^1{\left(\frac{1}{2}\right)}^4$

$=\frac{6}{32}$