Aptitude - Pipes and Cistern - Discussion

a,b,c,d=pipes 6 hrs time
a is taken=3 hrs time
a+a+b+c=3hrs each one taken 45 min
final 3hrs+45min

How you write 45min lekha please can you explain me the logic, Im not getting it.

Can anybody explain ths clearly?

NOTE:
1 tap takes 6hours....now by using four similar such taps it take 3/2 hours to fill the tank......
since all of them are capable of filling the tank in 6 hours)therefore they share time equally----6hours/4taps=3/2 hours )

now lets go to the solution:::

to fill half of the tank...only one tap is used...therefore it takes 3hours.
now 3 more similar taps are used...means now we are using 4 taps which are of same kind..
as explained above..
to fill the tank by the use of four taps----it takes 3/2 hours
now what we require is just to fill the half of the tank
it takes 3/4 hours i.e [3/2]/[1/2]=3/4
threfore we get---3+3/4 means 3 hours 45 min

Can any one explain clearly this ?

@MANASA

How can you write [3/2]/[1/2]= 3/4 ?
Its 3 not 3/4.

How can we write 2/3:1/2::1:x?

A pipe can fill the tank in 6 hours, so in 1 hour the pipe can fill 1/6 th part of the tank.

1 hour--------->1/6 part of tank.

3 hours--------->1/2 part of tank.

According to the data which had given in the question:The similar three more taps are opened so total number of taps are:4.

These four taps together in hour can fill (1/6+1/6+1/6+1/6=4/6=2/3) 2/3 part of the tank.

So, total time equals to 3.75 hours which is equals to 3 hours 45 minutes.

1 hour--------->1/6 part of tank.

3 hours--------->1/2 part of tank.

So 1/2 already filled and 1/2 has to be filled.

Now 4 similar taps are opened so total time taken is (1/6+1/6+1/6+1/6) =2/3.

Time to fill remaining 1/2 is 1/2=2/3*x.

X=3/4=.75.

Thus total time taken= 3 +.75 = 3.75.

1 tap has filled half of the tank in 3 hours and remained half of the tank have to be fill by 4 taps and we know that tank will take total 6 hours to fill. So, now remaining time is 3 hours that is 180 minutes and we have 4 taps so the solution is 180/4=45 min that is the tank taken total time is previous 3 hours that is filled by only 1 tap and by 4 taps is 45 mins.

So the total time is 3 hours and 45 mins.