SOLUTION: a combo deal at the local pizza store allows you to add up to three toppings on your pizza. If there are 9 toppings to choose from, how many different topping combinations are poss

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Question 1079188: a combo deal at the local pizza store allows you to add up to three toppings on your pizza. If there are 9 toppings to choose from, how many different topping combinations are possible?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
C( 9,3 ) = +9%21+%2F+%28+3%21%2A%28+9+-3+%29%21+%29+
C( 9,3 ) = +9%21+%2F+%28+3%21%2A6%21+%29+
C( 9,3 ) = +%28+7%2A8%2A9+%29+%2F+%28+1%2A2%2A3+%29+
C( 9,3 ) = +504%2F6+
C( 9,3 ) = +84+
84 combinations are possible with 3 toppings
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You also might have 2 toppings:
C( 9,2 ) = +9%21+%2F+%28+2%21%2A%28+9+-2+%29%21+%29+
C( 9,2 ) = +9%21+%2F+%28+2%21%2A7%21+%29+
C( 9,2 ) = +%28+8%2A9+%29+%2F+2%21+
C( 9,2 ) = +36+
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You might have 1 topping:
C( 9,1 ) = +9%21+%2F+%28+1%21%2A%28+9-1+%29%21+%29+
C( 9,1 ) = +9%21+%2F++8%21+
C( 9,1 ) = +9+
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Adding up the combinations:
+84+%2B+36+%2B+9+=+129+ possible
( get another opinion if needed )