Every staff in an office owns either a Mercedes and/or a Toyota car. 20 own Mercedes, 15 own Toyota and 5 own both. How many staff are there in the office?
A.
25
B.
30
C.
35
D.
45
Correct answer is B
M = Mercedez; T = Toyota
Number of staff = 0 + (20 - 5) + (15 - 5) + 5
0 + 15 + 10 + 5 = 30