A pipe, opened on an empty tank, fills \(\frac{2}{5}\) of the tank in 6 minutes. The pipe is kept open at the same rate. In how many more minutes will the tank be full?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 9 minutes
The pipe keeps the same rate, so the time is in proportion to the part still to be filled.
\(\frac{2}{5}\) of the tank takes 6 minutes, so \(\frac{1}{5}\) takes \(3\) minutes
Part still to be filled \(\displaystyle =1-\frac{2}{5}=\frac{3}{5}\)
Time for \(\frac{3}{5}\) \(=3\times3=9\) minutes
The tank is full in 9 more minutes.