A company that produces rivets used by commercial aircraft manufacturers knows that the shearing strength (force required to break) of its rivets is of major concern. The company believes the shearing strength of its rivets is normally distributed with a mean of 925 pounds and a standard deviation of 18 pounds.

a. If the company is correct, what percentage of its rivets have a shearing strength greater than 900 pounds?

b. What is the upper bound for the shearing strength of the weakest 1% of the rivets?

c. If one rivet is randomly selected from all of the rivets, what is the probability that it will require a force of at least 920 pounds to break it?

d. Using the probability found in part

c, rounded to nearest tenth, what is the probability that 3 rivets in a random sample of 10 will break at a force less than 920 pounds?