Question 354012
let it take x hours to fill the tank when inlet alone is open
it does 1/x of the job in 1 hour.
..
it will take (x+2) hours to drain when only drain is open
..
so 1/(x+2) of the job is done in 1 hour
..
it takes 8 hours to do the job when both are open
1/x-1/(x+2)= 1/8
x+2-x / x(x+2)=1/8
2/x(x+2)=1/8
16=x(x+2)
16=x^2+2x
x^2+2x-16=0
solve using quadratic formula
determinant = 68
-2+sqrt68 /2
=3.1 

x=3.1
draining = 3.1+2 =5.1 hours

..
m.ananth@hotmail.ca