A pair of dice is thrown 4 times. If ‘getting a doublet’ is considered a success, find the probability of getting 2 successes.
As the pair of die is thrown 4 times,
The total number of outcomes = 36
Using Bernoulli’s Trial P(Success=x) = nCx.px.q(n-x)
x=0, 1, 2, ………n and q = (1-p)
The probability of success = p = 
q = 
probability of 2 successes = 4C2.(
)2(
)2
⇒ 
1