Question

In four schools $B_1,B_2,B_3,B_4$ the percentage of girls students is 12, 20, 13, 17 respectively. From a school selected at random, one student is picked up at random and it is found that the student is a girl. The probability that the school selected is $B_2$, is

• A. $\frac{6}{31}$
• B. $\frac{10}{31}$
• C. $\frac{13}{62}$
• D. $\frac{17}{62}$

Answer 1

The correct option is B $\frac{10}{31}$

Favorable number of cases = ${}^{20}{C}_1=20$
Sample space = ${}^{62}{C}_1=62$
$\therefore$ Required probability = $\frac{20}{62}=\frac{10}{31}$