Question

A pair of dice is thrown 3 times. If getting a doublet is considered a success, find the probability of getting at least two success.

Solution:

A pair of dice is thrown 3 times.

∴ n = 3

Let x = number of success (doublets)

p = probability of success (doublets)

∴  p = `square`, q = `square`

∴ x ∼ B (n, p)

P(x) = ⁿC_xp^x q^n–x

Probability of getting at least two success means x ≥ 2.

∴ P(x ≥ 2) = P(x = 2) + P(x = 3)

= `square` + `square`

= `2/27`

Answer 1

A pair of dice is thrown 3 times.

∴ n = 3

Let x = number of success (doublets)

p = probability of success (doublets)

∴  p = `bb(1/6)`, q = `bb(5/6)`

∴ x ∼ B (n, p)

P(x) = ⁿC_xp^x q^n–x

Probability of getting at least two success means x ≥ 2.

∴ P(x ≥ 2) = P(x = 2) + P(x = 3)`

= `bb(15/216)` + `bb(1/216)`

= `2/27`