An average tire used by a transportation company lasts 20,000 km with a standard deviation of 100 km. Assuming that the distance traveled by a tire is normally distributed, what is the probability that a tire used by the company wil| last at most 30,000 km?

Assume that the square footage of a residential house in the US is normally distributed with a mean=1000 and standard deviation=150 square feet. If we select a random house what is the probability that it will be at most 1050 square feet?

The lengths of pregnancies are normally distributed with a mean of 266 days and a standard deviation of 20 days. If 64 women are randomly selected find the probability that they have a mean pregnancy between 266 days and 268 days

Birthweight at a hospital were reported to have a mean of 3668 grams (g) and a standard deviation of     511 g. These birthweights are normally distributed.  Find the probability that a single baby's birth weight was less than 4000 g.

The time for an event for girls in secondary school is known to posses a normal distribution within a mean of 450 seconds and a standard deviation of 50 seconds.  Find the probablity that a randomly selected girl in a secondary school will take longer 335 seconds to run the mile

do number (d), (e), and (f) please

The migratory habits of zebra in the savanna are normally distributed with a mean of 238 days and a standard deviation of 13 days. Find the probability a single zebra will migrate in less than 220 days.