the maximum speed X of a moped can be modeled with a normal

the maximum speed X of a moped can be modeled with a normal distribution with mean value 46.8 km/h and standard deviation 1.75 km/h. if a moped is selected randomly

A) what is the probability that the maximum speed is at most 59 km/h?

B) what is the probability that the maximum speed is at least 48 km/h?

C) suppose 5 mopeds are randomly selected. what is the probability that exactly 3 of the 5 have a maximum speed of at least 48 km/h?

Solution

z-score for speed atmost 59 km/hr is 6.9714

P(x)=1-6.9714

=-5.9714

z-score for speed atmost 48km/hr is .6857

P(x)=1-.6857

=0.3143