Question 439004
There are two ways to look at this problem 
from the point of view of the water or from the view of the acid.
45% acid is 55% water
pure 100% water is 0% acid
15% acid is 85% water
I will show you view from water
x+1000=y
1000*.55+x=.85*y
x=2000 and y=3000
so add 2000 ml of water