Adam will use x black stone tiles and y gray stone tiles to cover his patio floor. black stone tiles cost $5 each and gray stone tiles cost $4 each. he can spend up to $150 on his project, and he wants the number of gray stone tiles to be less than half the number of black stone tiles.

An arc subtends a central angle measuring 7pi/4 radians what fraction of the circumference is this arc?

Asquare has a side that measures 11 units. what is the area of a circle with a circumference that equals the perimeter of the square? use 3.14 for π, and round your answer to the nearest hundredth. 1519.76 units2 379.94 units2 616.56 units2 154.14 units2

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.