4) A skate park charges $5.00 for admission and $0.75 for each hour at the park. If Rolina spends
a total of $7.25 at the park, how long was she
there?

Find the midpoint m of z1=(8+5i) and z2=(12+3i)

What is the frequency of the sinusoidal graph?

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.