IQ scores are known to be normally distributed with a mean of 100 and a standard deviation of 15.

13. Approximately what are the IQ scores that cut-off the upper and lower 3% of the population?

a. 28.90; 150.25

b. 60.80; 134.90

c. 71.80; 128.20

d. 120.45; 82.15

14. Approximately what is the probability of selecting a person with an IQ of 125 or greater from this population?

a. 4.75/100

b. .0225

c. .1050

d. 83/100

Can you please explain why the answers are c and a respectively? thanks :)