Four student's grades changed after the last test. Which student's grade changed the least? Student A: from 92% to 95% Student B: from 87% to 81% Student C: from 98% to 94% Student D: from 82% to 87%

The sum of two numbers is 86, and their difference is 20. find the two numbers

Match each inequality to the number line that represents its solution

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.