SOLUTION: If you had 13 toppings how many different 4 topping pizzas can you make

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Question 624539: If you had 13 toppings how many different 4 topping pizzas can you make
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Use the combination formula...

n C r = (n!)/(r!(n-r)!)

13 C 4 = (13!)/(4!*(13-4)!)

13 C 4 = (13!)/(4!*9!)

13 C 4 = (13*12*11*10*9!)/(4!*9!)

13 C 4 = (13*12*11*10)/(4!)

13 C 4 = (13*12*11*10)/(4*3*2*1)

13 C 4 = (17160)/(24)

13 C 4 = 715

So there are 715 different pizzas you can make.