Answer
The number of ways to form password with four different letters without repetition = 35
Work Step by Step
Given letters = A, B, C, D, E, F, G = 7
The number of ways to form password with four different letters without repetition
$7_{{P}{_{4}}}$ = $\frac{7!}{(7 - 4)! 4!}$
= $\frac{7\times6\times5\times4\times3!}{3! .4\times3\times2\times1}$ = 35
