In four schools B1, B2, B3, B4 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 B2, is

Question

In four schools B1, B2, B3, B4 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 B2, is (A) (6/31) (B) (10/31) (C) (13/62) (D) (17/62)

Tardigrade Admin · Accepted Answer

Total no. of students in four schools = 12 + 20 + 13 + 17 = 62. Now, one student is selected at random. ∴ Total outcomes = 62C1 No. of ways to select a student from B2 = 20C1 ∴ Required probability =(20C1/62C1)=(20/62)=(10/31)

Q. 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

$\frac{6}{31}$

$\frac{10}{31}$

$\frac{13}{62}$

$\frac{17}{62}$

Total no. of students in four schools $= 12 + 20 + 13 + 17 = 62.$
Now, one student is selected at random.
$∴$ Total outcomes $= 6 2_{C_{1}}$
No. of ways to select a student from $B_{2} = 2 0_{C_{1}}$
$∴$ Required probability $= \frac{2 0 _{C_{1}}}{6 2 _{C_{1}}} = \frac{20}{62} = \frac{10}{31}$

Q. In four schools B1​,B2​,B3​,B4​ 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 B2​, is

316​

3110​

6213​

6217​