Brett, Lucy, and Jim are each carrying bags of mulch to flower beds. It takes Brett 35 minutes to carry one, Lucy 28 minutes to carry one, and Jim 7 minutes to carry one. How many minutes will pass before they arrive at the same time?

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.