There are 5 doors to a lecture room. Two are red and the others are green.In how many ways can a lecturer enter the room and leave the room from different colored doors?
(A)3(B)6(C)12(D)24(E)18

• Option C:12
  If he enters from red door, he has the option to leave from the green door in 3 ways. Thus, in toto, he has 2*3=6ways
  Similarly, from green door entry and exit from the door, He has 6 ways
  Thus, in total there are 12 ways.
• 12 years agoHelpfull: Yes(2) No(0)