Oh, isn't that a happy little question! With 7 elements, you can create many arrays by arranging them in different orders. The number of different arrays you can make out of 7 elements is 5040. Just imagine all the beautiful possibilities waiting to be painted on your canvas of creativity!
Oh, dude, there are like a bazillion different arrays you can make with 18. Okay, maybe not a bazillion, but definitely a lot. You can have arrays like [1, 2, 3, 4, 5, 6], [18], [9, 9], or even [2, 9, 7]. The possibilities are endless... well, not really, but you get the point.
15
7 different notes.
1*422*21 3*146*7
The answer is 7C5 = 21.
Oh, dude, there are like a bazillion different arrays you can make with 18. Okay, maybe not a bazillion, but definitely a lot. You can have arrays like [1, 2, 3, 4, 5, 6], [18], [9, 9], or even [2, 9, 7]. The possibilities are endless... well, not really, but you get the point.
3 or 7 - depending on whether you count a transposed array as different. 1*64 2*32 4*16 8*8
4 (or eight if you count transposed arrays as being different).
15
7 different notes.
1*422*21 3*146*7
The answer is 7C5 = 21.
7
identify two composite numbers that each have 8 as a factor
it is 1 7 tens 1 fives
7
7