You are ordering a hamburger and can get up to 7 toppings, but each topping can only be used once. You tell the cashier to surprise you with the toppings you get. What is the probability that you get 2 toppings
+130536 We can use the 7th row of Pascal's Triangle to solve this
Number of Toppings Number of Possible Combos
0 1
1 7
2 21
3 35
4 35
5 21
6 7
7 1
Assuming that we can choose to have no toppings.....the probabilty of two toppings =
21 / 2^7 = 21/ 128
However...if we must have at least one topping the probability of getting two toppings =
21 / [ 2^7 - 1] = 21/ 127
