SOLUTION: The number of hours the outlet of a water tank takes to empty it is the square of the number of hours the inlet takes to fill it. There are two such identical tanks. One is filled

Algebra ->  Rate-of-work-word-problems -> SOLUTION: The number of hours the outlet of a water tank takes to empty it is the square of the number of hours the inlet takes to fill it. There are two such identical tanks. One is filled       Log On


   

Question 384750: The number of hours the outlet of a water tank takes to empty it is the square of the number of hours the inlet takes to fill it. There are two such identical tanks. One is filled and the other is empty. The outlet of the full tank is opened at 8 AM. At the same time, both the inlet and the outlet of the empty tank are also opened. If the empty tank got full and the full tank got completely emptied at the same time, what time of was it?
1 PM

2 PM

12 noon

10 AM//

very tuff
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi,         

Let n and  n^2  represent time to fill and empty the tank respectively

Question States*** 

  1) BOTH INLET and OUTLET are open with the tank to FILL! AND..

2) Time/hr FILLING the empty tank = Time/hr emptying full tank

 both inlet and outlet valves open

         1/n - 1/n^2              =   1/n^2 

 1%2Fn+=+2%2Fn%5E2  Cross Multiply

  2n = n^2  

   2hr = n  

The outlet of the full tank is opened at 8 AM, n^2 = 4hrs, the time to empty

Full Tank would be empty at 12 Noon 

and the other Full(with both inlet and outlet open)



CHECKING our Answer***

 1/2 - 1/4 = 1/4