Help 1,2,3 ​

3. 7C6= 7!/6! * 1!= 7/1=7, so the last option.

1.    3 routes from school to library * 5 routes from library to home  =   15

2.  Possible ways that Verne can line up his books = 6!  = 720

     Possible ways that  Jenny can line up her books  = 4!  = 24

720  -  24     =    696