Im having a blonde moment help me plz

Julius sold five times as many computers as sam sold last year. in total, they sold 78 computers. how many computers did julius sell?

What is the volume of a cone with a height of 6 cm in the radius of 2 cm

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.