Solve for n
P (n,5) = 42 x P(,3)
.. This is from a grade 12 Data Management course that I am taking online! Other people have tried to help me on a different forum, but I still don't know what to do!
I assume by P(,3) you meant P(n, 3). I assume that the notation represents permutations. You should know a basic formula which allows the equation to be written as
Now you have three choices:
Option 1: Guess and check. When you get to n = 10 you'll have the answer.
Option 2: By definition of the factorial, the equation can be written as
.
Therefore n = 10 (the negative solution is rejected).
Option 3: Note that . Therefore . This suggests that the left and right hand sides are equal to 7!. Hence n = 10. Check it ..... Correct.