The weekly amount spent for maintenance and repairs in a certain company was observed, over a long period of time, to be approximately normally distributed with a mean of $400 and a standard deviation of $20.
A: If $450 is budgeted for next week, what is the probability that the actual costs will exceed the budgeted amount?
B: What is the 40th percentile for this distribution?
C: What is the probability next weeks costs will be equal to the average?
D: What is the probability next weeks costs will be under the amount budgeted but greater than $375?