Question

In a second grade class containing 12 girls and 11 boys, 2 students are selected at random to give out the math papers. what is the probability that both are girls?

Answer 1

The probability is defined as
`(number OfFavourableEvents)/(numberOfEvents In TheSampleSpace)`.

The number of ways of selecting 2 girls from 12 girls is
`C(2,12)=(12!)/(10!2!) =66`.The number of ways of selecting 2 student from
`12+11=23` students is
`C(2,23)=(23!)/(21!2!) =253`.

The required probability is
`(66)/(253) =(6)/(23) =0.261`