Kristine bought a vase that cost $5.99 and roses that cost $1.25 each. The total cost was $20.99.

Write an equation to find the number of roses purchased. Use r to represent the number of roses. You do not need to solve the equation.

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.