How Does the Continuity Equation Apply to Changing Water Flow in Pipes?

[dinhjeffrey]

Homework Statement

http://img41.imageshack.us/i/1721001.jpg/
#18

Homework Equations

proportions

The Attempt at a Solution

i would think water flowing is directly proportional to the diameter so i got
V1/D = V2/d
V2 = d*V1/D
but the answer is E

 

[rock.freak667]

Do you know the continuity equation Av= constant such that A₁v₁=A₂v₂ ?

and A = πd²/4