Question

PLEASE HELP ME!

5.

Find the number of two-letter permutations of the letters.


Q, I, E, R, T, Y, U



5,040


1,208


14


42

Answer 1

42

Explanation:

The permutation for that set of data looks like this:

`_(7)P_(2)`

The formula looks like this:

`_(7)P_(2)=(7!)/((7-2)!)`

which of course simplifies to

`_(7)P_(2)=(7!)/(5!)`

which further simplifies down to the most basic simplification:

`_(7)P_(2)=7*6`

since the 5*4*3*2*1 that goes after the 6 in the numerator cancels with the 5*4*3*2*1 in the denominator.

You could also check this on your calculator. Hit "math", then arrow over to "Prob" and it's under nPr.