Question

In a class there are 15 boys and 10 girls.three students are selected at random what is the probability that 1 girl and 2 boys are selected?​

Answer 1

Step-by-step explanation:

this question is of which class

Answer 2

Step-by-step explanation:

First we calculate In how many ways 3students can be selected out of 25 students( 15 boys + 10 girls)

Total no of ways = 25C3 = (25!) / {(25–3)! * 3!}

= (25*24*23*22*21 . . . ) / ( 22*21… ) * (3*2*1)

=( 25 * 24*23) / 6

= 100 * 23

= 2300 ways . . . . . . . .(1)

Now, 1 girl can be slected out of 10 girls in 10C1 ways.

& 2 boys can be selected out of 15 boys in 15C2 ways.

=> favourable number of ways = 10C1 x 15C2

= (10!/9!) x ( 15! /13! X 2! )

= 10 * 15 * 14 /2

= 1050 ways . . . . . . .( 2)

=> Probability of picking 1girl & 2 boys = favourable ways / total no of ways

=> P( E) = 1050/ 2300 = 21/46 . . . . . . Ans