How often should septic tanks be pumped on average?Group of answer choicesEvery 6–10 yearsEvery 3–5 yearsEvery 1–2 years

4 pipes can fill a tank in 15, 20, 30 & 60 hours respectively. The first was opened at 6 a.m., second at 7 a.m., third at 8 a.m. and fourth at 9 a.m. When will the tank be full?

9 pipes are required to fill a tank in 4 hours. How long will it take if 12 pipes of the same type are used?Choices:-

Three pipes can fill a tank in 6, 10, 15 hours respectively. If they are opened together, how long does it take to fill the tank?

A tank is filled by three pipes with uniform flow. The first two pipes operating simultaneously fill the tank in the same time during which the tank is filled by the third pipe alone. The second pipe fills the tank 5 hours faster than the first pipe and 4 hours slower than the third pipe. The time required by the first pipe is:6 hours10 hours15 hours30 hours

A total of 7 inlet and outlet pipes are fitted to a tank. Each inlet pipe can fill the tank (when empty) in 24 hours. Each outlet pipe can empty the tank (when full) in 36 hours. If all the pipes are opened simultaneously, the tank which is initially empty will be filled in 12 hours. The number of inlet pipes fitted to the tank is _____.