A pipe can fill a tank in 12mins and anothe pipe in 18 mins, but a third can empty it in 7 mins
Answers
pls give the complete question thank u
nswer is 3 minutes.
Now coming to the solution, there are two method to solve this question:-
1st method is similar to the one taught in school.
Suppose the volume/capacity of tank be V litres.
Pipe A fills the tank in 4 minutes. So in 1 minute it will fill V/4 litres of tank ( using unitary method).
Similarly, Pipe B fills the tank in 12 minutes. So in 1 minute it will fill V/12 litres of tank.
Now, Pipe A and Pipe B together in 1 minute will fill (V/4 +V/12) litres of the tank.
Therefore, in 1 minute, V/4+V/12= 4V/12 or V/3 litres of tank.
Again using Unitary method, V/3 litres is filled in 1 minute. So, V litres will be filled in 3 minutes.
2nd method is used to solve quickly for competitive exams.
Calculate the LCM of 4 and 12 given in the question. It will be 12.
Consider this 12 as the total capacity of the tank.
Now if Pipe A fills 12 litres in 4 minutes, then in 1 minute it will fill 3 litres.
Similarly, if Pipe B fills 12 litres in 12 minutes, then in 1 minute it will fill 1 litre.
Together Pipe A and Pipe B in 1 minute fill 3 litres+ 1 litre= 4 litres.
So to fill 12 litres, they will take 12/ 4= 3 minutes.
this is similar but if u give full question ican answer