Recall the formula for a permutation, _n P_r = n!/(n-r)!.
90
Practice makes perfect
To evaluate the given permutation, we will use the corresponding formula.
_n P_r = n!/(n-r)!
We are given that n=10 and r=2. Let's substitute these values into the formula.
We can evaluate the number of permutations _(10)C_2 using the graphic calculator. To do so, we have to start by entering the number of items, which is equal to 10.
Next, we push MATH and then scroll right until we reach PRB. Then, scroll down to the second row and push ENTER.
Finally, by entering the number of items to be chosen and hitting ENTER, we can calculate the number of permutations.
