Look up what is mean and calculate it.
Answer:
1/2
Step-by-step explanation:
1/4=2/8
2/8+2/8=4/8=1/2
Answer: 0.0336
Step-by-step explanation:
Given : The distribution of cholesterol levels in teenage boys is approximately normal with mean :
Standard deviation : 
The formula for z-score is given by :-

For x=225

The p-value =

The probability that a teenage boy has a cholesterol level greater than 225 =0.0336
10% of 5000 is 500 and 500 times 8 is 4000 so the total amount due would be 9000 :)