Answer
given,
Probability of loosing data, p = 0.005
q = 1 - 0.005 = 0.995
a) Probability that none of the need resent in the 100 Pack
= ¹⁰⁰C₀ p⁰q¹⁰⁰
= 0.995¹⁰⁰ = 0.6057
Probability at least one mail is resent = 1 - 0.6057
= 0.3942
b) Probability that that exactly one out of three needs to be resent is:
= ³C₁ p¹q²
= 3 x 0.005 x 0.995²
= 0.0149
c) Probability that none of the need resent in the 1000 Pack
= ¹⁰⁰⁰C₀ p⁰q¹⁰⁰⁰
= 0.995¹⁰⁰⁰ = 0.006657
Probability at least one mail is resent = 1 - 0.006657
= 0.9933