The volume of water in a certain tank is x percent greater than it was one week ago. If r percent of the current volume of water in the tank is removed, the resulting volume will be 90 percent of the volume it was one week ago. What is the value of r in terms of x? Choices:
A) x+10
B) 10x+1
C) 100(x+10)
D) 100( x+10/x+100)
E) 100 ( 10x+1/10x+10)
Given that, the water was increased by x percent -&gt; then reduced by r percent -&gt; to 90 percent of what it was one week ago.   Consider, the 100 units of water was increased by 20% to 120 units -&gt; then reduced by 25% of 120 (i.e. by 30 units) -&gt; to 90 units.   i.e. Pick numbers as x = 20% and r = 25%   Substitute x=20 and identify the answer that gives r=25   A) x+10 --20+1=30   b) 10x+1 --200+1=201   c) 100(x+10) --100(20+10)=3000   d) 100( x+10/x+100) --100(20+10/20+100) = 100(30/120)=25   e) 100 ( 10x+1/10x+10) -- 100(200+1/200+10)= 100(201/210)   Hence choice(100( x+10/x+100)) is the answer.
<result>D</result>
The volume of water in a certain tank is x percent greater than it was one week ago. If r percent of the current volume of water in the tank is removed, the resulting volume will be 90 percent of the volume it was one week ago. What is the value of r in terms of x?