Question

In a class of 45 students 15 are boys and rest are girls. Find the probability that a student chosen at

random is 

(a) a boy 

(b) a girl
​

Answer 1

Answer:

P(boys)=15/45=3/9=1/3

(girls) =45-15=35

P(girls)=30/45=6/9=2/3

Answer 2

The probability that a student is chosen at random is

(a) a boy = 1/3

(b) a girl = 2/3

Given:

The total number of students in a class is 45 students

The number of boys = 15

To find:

The probability when

(a) a boy is chosen

(b) a girl is chosen

Now,

Total number of students in the class = 45

That means, Boys + girls = Total students

⇒ 15 + girls = 45

⇒ girls = 45 - 15

∴ The number of girls in the class is 30

So,

• When a boy is chosed at random.

Number of favorable outcome = 15 (boys)

P(a boy) = [faborable otcome]/[Total number of possible outcomes]

P(a boy) = 15/45 = 1/3

And,

• When a girl is chosen at random.

Number of favorable outcomes = 30 girls

P(a girl) = [Total number of girls]/[Total number of students]

P(a boy) = 30/45 = 2/3