Students admitted in the decision science major of a public university are normally distributed with a mean of 150 and standard deviation of 15 in the quantitative section of GRE. The university admitted 250 students. Those who earned above 168 in the quantitative section of the GRE get 50% tuition waiver and those who earned 160 and above but below 168 get 25% waiver.
a. How many students get a 50% waiver?
b. How many students get a 25% waiver?