A tank initially has an unknown volume of water when it is being filled. After 5 minutes it contains 4000L. After 15 mins it has 6000L of water. What is the initial volume of the tank?

Question

dumbcow · Answer

Let x be initial volume , let r be rate per min water is increasing

x + 5r = 4000
x +15r = 6000

subtract equations...
10r = 2000
r = 200

thus
x = 3000

anonymous · Answer

How can the initial volume  be less than what the volume is 5 minutes later?

anonymous · Answer

@dumbcow