Each participant in a certain study was assigned a sequence of 3 different letters from the set {A, B, C, D, E, F, G, H}.  If no sequence was assigned to more than one participant and if 36 of the possible sequences were not assigned, what was the number of participants in the study?  (Note, for example, that the sequence A, B, C is different from the sequence C, B, A.)

In 1995 a certain store had 1,800 tools in stock that had been purchased for $30 each.  If 1,000 of these tools were sold in 1995 for $40 each and the remaining 800 were sold in 1996 for $50 each, how many greater was the gross profit on the tools sold in 1996 than the gross profit on those sold in 1995?

If xy ≠ 0 and x²y² – xy = 6, which of the following could be y in terms of x?

I.   ~$\frac{1}{2x}$~

II.  ~$-\frac{2}{x}$~

III. ~$\frac{3}{x}$~

150, 200, 250, n
Which of the following could be the median of the 4 integers listed above?

I.   175
II.  215
III. 235

A small, rectangular park has a perimeter of 560 feet and a diagonal measurement of 200 feet.  What is its area, in square feet?

$$M = (-6, -5, -4, -3, -2)$$

$$T = (-2, -1, 0, 1, 2, 3)$$

If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

The sum of all the integers k such that –26 < k < 24 is

Each of the 30 boxes in a certain shipment with either 10 pounds or 20 pounds, and the average (arithmetic mean) weight of the boxes in the shipment is 18 pounds.  If the average weight of the boxes in the shipment is to be reduced to 14 pounds by removing some of the 20-pound boxes, how many 20-pound boxes must be removed?

R, S, T, and U are points on a line, and U is the midpoint of line segment ST.  If the lengths of line segments RS, RT, and ST are 20, 4, and 24, respectively.  What is the length of line segment RU?

Company P had 15 percent more employees in December than it had in January.  If Company P had 460 employees in December, how many employees did it have in January?