For the first digit there are 7 choices. For the second digit there are 6 choices (because we can't use the same one again). And so on, until there is only one choice for the last digit.
The number of possible codes is this:
7*6*5*4*3*2*1 = 7! = 5040
It’s B.
Distribute the 7a and multiply it with the 3a and -4 a. With the exponents you add them.
Tristan’s is dk Oz Oz em on u e acc what
Write and solve an equation of ratios:
5 65
--- = ------
4 x
Then 5x = 260, or x = 52. There are 52 girls on the team. Note, as a check, that 65/52 reduces to 5/4, as it must.
D. 40
follow the pattern
1 band director calls 3 members. = 4
Each member calls 3 more members 3(3) = 9
Then each of those 9 call 3 more members 9(3) = 27
Add them up
4+9+27 = 40
