A rectangular community swimming pool is meters long and meters wide. The area around the swimming pool is covered with tiles. The area covered with tiles is 25% of the total area covered by the swimming pool. The total cost of the tiling is $712.50. What is the cost of the tiling per square meter?

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.