Suppose you deposit $1500 in a savings account that pays interest at an annual rate of
6%. No money is added or withdrawn from the account.
a. How much will be in the account after 5 years?
b. How much will be in the account after 20 years?
c. How many years will it take for the account to contain $2500?
d. How many years will it take for the account to contain $4000?

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.