Hhhheeelp pls (2)

The graph represents the gallons of water in a water tank with respect to the number of hours since it was completely filled

Aword processing program requires a 7- digit registration code made up of the digits 1,2,4,5,6,7 and 9 each number has to be used and no number can be used mor than once how many codes are possible

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)