Portuguese designer Miguel Neiva created a system of symbols that allows colorblind people to identify colors. The system consists of using symbols that identify primary colors (blue, yellow, and red). Furthermore, the juxtaposition of two of these symbols allows the identification of secondary colors (such as green, which is yellow combined with blue). Black and white are identified by small squares: the one that symbolizes black is filled, while the one that symbolizes white is empty. The symbols that represent black and white can also be associated with the symbols that identify colors, meaning whether these are light or dark.
According to the text, how many colors can be represented by the proposed system?
(A) 14
(B) 18
(C) 20
(D) 21
(E) 23

In a business meeting, each person shakes hands with each other person, with the exception of Mr. L. Since Mr. L arrives after some people have left, he shakes hands only with those present. If the total number of handshakes is exactly 100 , how many people left the meeting before Mr. L arrived? (Nobody shakes hands with the same person more than once.)

A solid cube of side five centimeters has all its faces painted. The cube is sliced into smaller cubes, each of side one centimeter. How many of these smaller cubes will have paint on exactly one of its faces?
(A) 25
(B) 54
(C) 126
(D) 150.

There are $m$ men and two women participating in a chess tournament. Each participant plays two games with every other participant. If the number of games played by the men between themselves exceeds the number of games played between the men and the women by 84 , then the value of $m$ is :
(1) 11
(2) 12
(3) 7
(4) 9

In a tournament with 8 teams, each team played against the other teams once. In the tournament, 3 referees were assigned from 4 available referees for each match, and all referees worked an equal number of matches.
Accordingly, how many matches did each referee work?
A) 14 B) 15 C) 18 D) 20 E) 21