1.  The condition says that Bugs bunny run 9 times as fast as Elmer Fud:


    x = 9y,                         (1)


    where x is the Bugs bunny' speed and y is the Elmer Fud' speed.



2.  The condition also says that  


    x - y = 15  miles per hour.     (2)



3.  From (1)  and  (2) you have


    9y - y = 15,   or

    8y = 15,   which gives you the solution

    y =   miles per hour  is the Elmer Fud' speed.


4.  Then  x = 9y =  =  miles per hour is the Bugs bunny' speed.



Answer.  The Elmer Fud' speed is    miles per hour.