Jack played the first of a basketball game. Then, he played the final of the game.
Which equation can Jack use to find out how much of the game he played in all?
A.
to + b =D
b=0
B.
5
+
10
C.
+
10
D.
10
+
10

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?