An ice cream shop offers 7 toppings. How many 4-topping ice cream sundaes can you make?

A)11
B)28
C)30 <-- My answer
D)35

1 answer

combinations of 7 taken 4 at a time
C(7,4) = 7! /[ 4!(3!)]

= 7*6*5/(3*2) = 35