Answer: With 11 pipes, you need 31.82 minutes to fill the tank.
Step-by-step explanation:
Let's define R as the rate at which one single pipe can fill a tank.
We know that 7 of them can fill a tank in 50 minutes, then we have the equation:
7*R*50min = 1 tank
Whit this equation, we can find the value of R:
R = 1 tank/(7*50min) = (1/350) tank/min.
Now that we know the value of R, we can do the same calculation but now with 11 pipes.
Then the time needed to fill the tank, T, is such that:
11*(1/350 tank/min)*T = 1 tank
We need to isolate T.
T = 1 tank/(11*(1/350 tank/min)) = 31.82 min
With 11 pipes, you need 31.82 minutes to fill the tank.
