Question

There are 60 students in a class among which 30 are boys. In another class there are 50 students among which 25 of them are boys. If one from each class is selected, [2]

(a) What is the probability of both being girls ?
(b) What is the probability of having at least one girl?
Explain also

Answer 1

A).= 1/2 probability of selecting girls.

B).= 1/2

Explanation:

because there are 30 boys out of sixty which makes it half the class.

then theres 25 boys out of 50. therefore the answer is 1/2

Answer 2

a) Probability of both being girl = 1/4

b) Probability of having atleast one girl = 1

Explanation:

Let name the two classes: Class A and Class B respectively.

Class A = 60 students, 30boys and 30girls

Class B = 50 students, 25boys and 25girls

a) Probability of both being girls=

Probability of selecting girl in Class A * Probability of selecting girl in Class B

Probability of both being girls = 30/60 * 25/50

= 1/2 x 1/2

= 1/4

Probability of both being girls = 1/4

b) probability of having atleast one girl = Probability of selecting girl in Class A + Probability of selecting girl in Class B

Probability of both being girls = 30/60 + 25/50

= 1/2 + 1/2

= 1

Probability of having atleast one girl = 1