# Pipe and cistern shortcut formula part 3

We hope that you have enjoyed the previous two tutorials, where we have shown you some basic concept and shortcut formula related to pipe and cistern math chapter. That is not enough for your upcoming competitive exam preparation for mathematics portion. Now, we are going to deliver more shortcut formula and competitive aptitude to observing this math chapter and prepare better for your upcoming competitive exam as well. Here, we will also use previous pipe and cistern shortcut formula but in different for the different questions, which has a great chance to ask on the competitive exam. So let’s see, some aptitude question related to Pipe and cistern math tricks.
Shortcut formula 1:
A tank connected with three pipes, when two pipes are the inlet and the rest is outlet pipe then the container can be full in:-

How to remember this formula? This is the big problem to memorize the shortcut formula. Just look at the denominator, multiplied with two inlet pipes by the outlet pipe, and then subtracted multiplication value of two inlet pipes.
Let see an example question and a tricky solution:-
Two outlet pipe A and B can fill a tank in 20 and 30 hours respectively. Another pipe is C, which is outlet pipe and it can empty the full tank in 60 hours. If all pipes are opened, then how long time they will take to fill the tank?

#### Solved Problems

Directly, you can solve the t using mentioned pipe and cistern math trick. First, two pipes are inlet pipes and time values are 20 and 30 hours respectively. The rest pipe is outlet pipe and its time value to empty a full tank is 60 hours. Now puts all the time value in the shortcut formula and simplify the value. Let’s look at below how the answer becoming easily.

Shortcut formula
A & B can fill a tank in x time unit, B & C can fill a tank in y time unit, and C & A can fill the same tank in z time unit then

same way B and C can do the work in

Have you shocked friends after looking at the shortcut formula? Don’t worry, we are giving you a mind mapping which will help you to remember easily. Just look at both photo and see every numerator is 2xyz. But in denominator takes a time value as common. How it has made? You can see that the workers are three couple. And finding the workability of a single person. We take the common(time value) in the denominator, the person(asked) who is not in the couple.

Hope you have learned all shortcut formulas which are provided in this post. In the next post, we will give a few more aptitude tricks which are very important for competitive aptitude. And then, we apply all formulas in exam level aptitude to earn full ability on pipe and cistern aptitude tricks and quicker solution.