There are two atoms of hydrogen and one atom of oxygen in one molecule of water. How many atoms of hydrogen are there in 51 molecules of water?

A photocopy machine is initially loaded with 5,000 sheets of paper. The machine starts a large job and copies at a constant rate. After 20 minutes, it has used  of the paper. Which of the following equations models the number of sheets of paper, p , remaining in the machine m  minutes after the machine started printing?

In a random sample of 200 cars of a particular model, 3 have a manufacturing defect. At this rate, how many of 10,000 cars of the same model will have a manufacturing defect?

Tracy collects, sells, and trades figurines, and she tracks the number of figurines in her collection on the graph below.

On what interval did the number of figurines decrease the fastest?

The 22 students in a health class conducted an experiment in which they each recorded their pulse rates, in beats per minute, before and after completing a light exercise routine. The dot plots below display the results.


Let   and  be the standard deviation and range, respectively, of the data before exercise, and let   and   be the standard deviation and range, respectively, of the data after exercise. Which of the following is true?

Solve each inequality and tell whether it has infinitely many or no solution :
-2(x-5)≥-2x+10

Solve each inequality and tell whether it has infinitely many or no solution:
0.5x+8<2x-4

Note:
A linear inequality could possibly have infinite number of solutions. But it is not necessary that it should be true for every inequality.

In the  -plane, the point  lies on the line with equation  , where b is a constant. The point with coordinates   lies on the line with equation  . If , what is the value of ?

One pound of grapes costs . At this rate, how many dollars will c pounds of grapes cost?

Triangles  ABC and DEF are shown above. Which of the following is equal to the ratio   ?

Solve each inequality and tell whether it has infinitely many or no solution:
-2x-5≥3x-25

Solve each inequality and tell whether it has infinitely many or no solution:
7.2x+6≤2.4x

Solve each inequality and tell whether it has infinitely many or no solution:
4(3-2x)≥-4

Solve each inequality and tell whether it has infinitely many or no solution:
-2(2x+1)<24

Solve each inequality and tell whether it has infinitely many or no solution:

To determine the mean number of children per household in a community, Tabitha surveyed 20 families at a playground. For the 20 families surveyed, the mean number of children per household was 2.4. Which of the following statements must be true?