Amanda can proofread 17 reports in an hour while Sally can proofread 28 reports in an hour if they have 420 reports to proofread how much time will it take between the two of them

Which matrix multiplication is possible?

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.

What is the value for this expression? 2e-5