Question

In a class of 28 students, 21 have a brother and 9 have a sister. There are 7 students

who have a brother and a sister. What is the probability that a student chosen
randomly from the class has a brother and a sister?

Answer 1

Explanation:

28 students in total

21 - 7 = 14 students only has a brother

9 - 7 = 2 students only have a sister

7 students have both brothers and sisters

probability of a student having a brother and a sister:

`(7)/(28) = (1)/(4)`

Answer 2

1/4

because not a lot of students have both gender as siblings!