Hans Solo, a navy admiral, has to choose 3 ships out of his fleet of 8 destroyer ships. In how many ways can this be achieved, assuming that he is not biased toward choosing any particular ship?
A. 120
B. 48
C. 56
D. 336
E. 256

• nCr = n! / (r!(n − r)!), where ! stands for the factorial notation.
  Since n = 8 and r = 3, the required number of ways is 8! / (3! 5!) = 8 x 7 x 6 / (3 x 2 x 1) = 56.
  Note that 8! = 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1; 3! = 3 x 2 x 1; and 5! = 5 x 4 x 3 x 2 x 1.
  
• 12 years agoHelpfull: Yes(0) No(0)