Question

A balloon vendor has 2 red, 3 blue and 4 green balloons. He wants to choose one of them at random to give it to Pranali. What is the probability of the event that Pranali gets, a blue balloon.

Answer 1

Given: Number of red balloon = 2

Number of blue balloon = 3

Number of green balloon = 4

Let S be the sample space.

∴ n(S) = Number of red balloon + Number of blue balloon + Number of green balloon 

= 2 + 3 + 4

= 9

Let B be the event of getting a blue balloon.

Given: n(B) = 3

∴  `"P"("B") = ("n"("B"))/("n"("S"))`

= `3/9`

= `1/3`

Hence, the probability of the event that Pranali gets a blue balloon is `1/3.`

Answer 2

Let the 2 red balloons be R₁, R₂,

3 blue balloons be B₁, B₂, B₃ and

4 green balloons be G₁, G₂, G₃, G₄.

∴ Sample space,

S = {R₁, R₂, B₁, B₂, B₃, G₁, G₂, G₃, G₄}

∴ n(S) = 9

Let B be the event that Pranali gets a blue balloon

∴ B = {B₁, B₂, B₃}

∴ n(B) = 3

∴ P(B) = `("n"("B"))/("n"("S"))`

= `3/9`

∴ P(B) = `1/3`

∴ The probability that Pranali gets a blue balloon is `1/3`.