Permutations or combinations? Combinations Answer: 15
Practice makes perfect
We want to find how many ways there are to select 2 out of 6 pizza toppings. Note that, in this case, the order is not important. Therefore, the situation involves combinations. To calculate the answer, we will use the formula for combinations of n objects taken r at a time.
_n C_r = _n P_r/r! ⇔ _n C_r = n!/(n-r)!r!
In our exercise, n= 6 and r= 2. Let's substitute these values into the above formula.
