Sylvia is changing the light bulbs of the big light fixture in her dining room. she finished 1 5 of the bulbs in 10 minutes. what fraction of bulbs does she have left to do? a) 1 5 b) 2 5 c) 3 5 d) 4 5

This is the number of parts out of 100, the numerator of a fraction where the denominator is 100. submit

Cora bought a package of erasers. there are 4 pink erasers and 12 blue erasers. what is the ratio of pink erasers to blue erasers?

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.