Please help! Will fan and medal! Thank you! :)

Five friends are having their picture taken. How many ways can the photographer arrange the friends in a row?
a. 150
b. 100
c. 120
d. 80

Question

Please help! Will fan and medal! Thank you! :) 

Five friends are having their picture taken. How many ways can the photographer arrange the friends in a row?
a. 150
b. 100
c. 120
d. 80

anonymous · Answer

@ganeshie8

irishboy123 · Answer

$$\frac{ n! }{ (n-r)! }$$

permutations, no repetition, n and r = 5...

anonymous · Answer

Oh, thanks! I wasn't sure how to solve it! :p So 5 = 5 x 4 x 3 x 2 x 1 = 120
Is that right?

irishboy123 · Answer

well done!

anonymous · Answer

Okay great! Do you think you can help me with one more question? :)