The diameter of a circle is 2 units What is the radius of the circle

If a baby uses 15 diapers in 2 days, how many diapers will the baby use in a year?

Jenisey has $24 to spend on seven pencils. after buying them she had $10. how much did each pencil cost.?

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.