megatron13 wrote:
7 people (A, B, C, D, E, F and G) go to a movie and sit next to each other in 7 adjacent seats in the front row of the theater.
How many different arrangements are possible? If A will not sit to the left of F and F will not sit to the left of E. How many different arrangements are possible.
A) 7!/2
B) 7!/3
C) 7!/4
D) 7!/5
E) 7!/6
Hi
debbiem,
Refer your PM..
For doing any of these Qs, the MEANING is most important..
what does ---- A will not sit to the left of F and F will not sit to the left of E -- mean.
Keep in mind- it does not talk of immediate left..so If I have a combination like
D,A,C,F,B,E,G.....
we are concerned about the position of A, F and E.. they have to be in ...E..F..A..
so If we keep the position of all other B,C,D, and G constant these 3- E,F and A can be arranged in 3! ways and ONLY one way ...E..F..A.. is correctso ONLY 1 out of 3! or 6...OR 1/6 are VALID
Same will be the case for all other arrangements of B,C,D, and G ..
so our answer will be TOTAL *VALID = 7!*1/6 = 7!/6....