Sixth grade
Because if you divide their total profit by the total amount of hours they worked, you would find that the sixth grade's income per hour is the highest.
Sixth grade: 170÷5=34
Seven grade: 112÷4=28
Eighth grade: 192÷6=32
The formula for yearly compound interest is A(1 + r)^t
Where is A = 1000, r = 8%, t = 20

The answer is $4660.96
Answer is option C 19.64 sq units
She asked her friends, which does not represent a random sample.
She tried to show cause and effect without doing an experiment (which includes simple random sample, control group, treatment, etc).
So the answer is she did not use a random sample, and tried to show cause and effect with an observational study.
Answer:
-1
Step-by-step explanation: I did something similar to this