This is the area of a triangle
Answer:
Step-by-step explanation:
Express Courier Service has found that the delivery time for packages is normally distributed. So we use
z = (x - mean)/standard deviation
mean = 13
standard deviation = 2
x = time of delivery in hours
a) P(0 lesser than/equal to 18)
z = (18-13)/2 =5/2 = 2.5
Using the normal distribution table, the value is 0.9938
b) to be 95% sure, let the time be t
From the table, the equivalent of z that is 0.95 = 1.645
So 1.645 = (t-13)/2
t-13 = 3.29
t = 3.29+13= 16.29 hours
The answer is 3/10 ( hope this helps)
