N-10+9n-3
n+9n=10n
10-3=7
so the answer is....
-13+10n
For part A, The answer is that the car gets better gas mileage. We can see it from the graph that the number of gallons used is on the X axis, and the distance traveled using those number of gallons is on the Y axis. The easiest way to compare would be to look at the 1 gallon of gas. You can see that you can travel 25 miles on 1 gallon of gas. The truck on the other hand will get you 18 miles per gallon. Imagine putting 1 in for X, the Y value would be 18 if you did this. The graph just shows us a visual way of saying the same thing. To determine how much farther the car with a girl on 8 gallons of gas, you would just multiply 8 by 25 for the number of miles traveled by the car. You would multiply 8 by 18 to find the number of miles traveled for the truck. The answers are 200 miles for the car and 144 miles for the truck. 200-144=56 miles farther for the car.
The empirical rule states that in a normal distribution,
68% of data is within 1 std deviation of the mean
95% of data is within 2 std deviation of the mean
99.7% of data is within 3 std deviation of the mean
In this case 95% of the cases would be within two std deviations of the mean
mean - 8 and mean + 8
72 - 8 = 64 and 72 + 8 = 80
then 95% of the scores are between 64% and 80% on the test.
42000 is the answet. that is all
