Question

Six mobsters have arrived at the theater for the premiere of the film "Goodbuddies." One of the mobsters, Frankie, is an informer, and he's afraid that another member of his crew, Joey, is on to him. Frankie, wanting to keep Joey in his sights, insists upon standing behind Joey in line at the concession stand, though not necessarily right behind him. How many ways can the six arrange themselves in line such that Frankie’s requirement is satisfied?

a. 6
b. 24
c. 120
d. 360
e. 720

Answer 1

D = 360

Explanation:

Number of monsters that arrive at the theater = 6

Total number of arrangement for the 6 mobsters = 6!

= 6*5*4*3*2*1

= 720

The chance that Frankie will be behind Joey is half while the chance that Joey will be behind Frankie is half.

Since Frankie wants to stand behind joey in the line though not necessarily behind him, the arrangement can be done in 6!/2 ways

= (6!) 1/2

= 720/2

= 360 ways