So in order to figure this out, you first need to figure out how many yards it is going per second. We can easily figure that out by doing 450 / 15. The answer to that is 30. Then, just figure out 1/3 of 30. That is also easy to find, and the answer to that is 10.
So your final answer to this is :
Ft. goes per 1/3 sec : 10 ft.
Operations used : 450 / 15 = 30 ; 1/3 of 30 = 10.
Hope this helped! <3