A pair of dice is thrown 7 times. If ‘getting a total of 7’ is considered a success, find the probability of getting
(i) no success
(ii) exactly 6 successes
(iii) at least 6 successes
(iv) at most 6 successes
(i) Using Bernoulli’s Trial P(Success=x) = nCx.px.q(n-x)
x=0, 1, 2, ………n and q = (1-p), n =7
the favourable outcomes ,
(1,6), (6,1), (2,5), (5,2), (3,4), (4,3)
The probability of success = p = 
q = 
probability of no success = 7C0.(
)0(
)7
⇒ (
)7
(ii) Using Bernoulli’s Trial P(Success=x) = nCx.px.q(n-x)
x=0, 1, 2, ………n and q = (1-p), n =7
the favourable outcomes ,
(1,6), (6,1), (2,5), (5,2), (3,4), (4,3)
The probability of success = p = 
q = 
probability of exactly 6 successes = 7C6.(
)6(
)1
⇒ 35.(
)7
(iii) Using Bernoulli’s Trial P(Success=x) = nCx.px.q(n-x)
x=0, 1, 2, ………n and q = (1-p), n =7
the favourable outcomes ,
(1,6), (6,1), (2,5), (5,2), (3,4), (4,3)
The probability of success = p = 
q = 
probability of at least 6 successes =
7C6.(
)6(
)1 + 7C7.(
)7(
)0
⇒ 36.(
)7
⇒ (
)5
(iv) Using Bernoulli’s Trial P(Success=x) = nCx.px.q(n-x)
x=0, 1, 2, ………n and q = (1-p), n =7
the favourable outcomes ,
(1,6), (6,1), (2,5), (5,2), (3,4), (4,3)
The probability of success = p = 
q = 
probability of at least 6 successes =
7C0.(
)0(
)7 + 7C1.(
)1(
)6 + 7C2.(
)2(
)5 + 7C3.(
)3(
)4 + 7C4.(
)4(
)3 + 7C5.(
)5(
)2 + 7C6.(
)6(
)1
⇒ (1- 
7)