Question

If the probability for A to fail in an examination is 0.2 and that for B is 0.3, the probability that either A or B fails,is

• A. 0.38
• B. 0.44
• C. 0.5
• D. 0.94

Answer 1

The correct option is B 0.44

$P\left(\overline{A}\right)=0.2,\overline{B})=0.3\therefore P(A)=0.8,P(B)=0.7$
$\therefore$ Required probability
$=P\left(\overline{A}\right)P\left(\overline{B}\right)+P\left(A\right)P\left(\overline{B}\right)+P\left(\overline{A}\right)P\left(\overline{B}\right)=0.2\times 0.7+0.8\times 0.3+0.2\times 0.3=0.44$