Mr. Robertson goes to Math Nerds R Us to buy 85 strands of normal algebra lights plus 40 strands of radioactive algebra lights. This trip costs him $169.75. His classroom isn't bright enough, so he returns to buy another 30 normal strands and 55 radioactive strands for an additional $98.75. How much does each type of strand cost?

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%

Abcd is a square. what is the measure of angle bac

An automobile assembly line operation has a scheduled mean completion time, μ, of 12 minutes. the standard deviation of completion times is 1.6 minutes. it is claimed that, under new management, the mean completion time has decreased. to test this claim, a random sample of 33 completion times under new management was taken. the sample had a mean of 11.2 minutes. assume that the population is normally distributed. can we support, at the 0.05 level of significance, the claim that the mean completion time has decreased under new management? assume that the standard deviation of completion times has not changed.