Question 1112565: Hi please guide me here: A Cape Town courier service promises that 20%of Johannesburg-bound parcel deliveries will reach
their destinations within 12 hours. What is the probability that of the seven parcels sent at random
times by a particular client in Cape Town, only one is delivered late?
Answer by rothauserc(4718)   (Show Source):
You can put this solution on YOUR website! use the binomial distribution
:
Probability ( P ) ( k successes in n trials ) = nCk * p^k * p^(n-k), where nCk = n! / (k! * (n-k)!)
:
for this problem, n=7, k=1, p = 1-0.20 = 0.80 (the probability of being late)
:
P ( 1 failure in 7 sent for delivery parcels ) = 7C1 * (0.80)^1 * (1-0.80)^(7-1)
:
P ( 1 failure in 7 sent for delivery parcels ) = 0.00036
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