A cistern can be filled by one tap in 4 hours and by another in 5 hours how long with it take to fill if both taps are opened together?
Answers
Answer:
We have,
Time taken by the first tap to fill the cistern =4 hours.
Time taken by the second tap to fill the cistern =3 hours
Work done by the first tap in 1 hour =
4
1
Work done by the second tap in 1 hour =
3
1
Thus, work done by both the taps in 1 hour =
4
1
+
3
1
=
12
3+4
=
12
7
Both the taps together will fill the cistern in
7
12
hours.
Answer:
20/9 hours
Step-by-step explanation:
since one tap can fill the cistern in 4 hours
therefore the work done by it in 1 hour will be 1/4
similarly the other tap can fill the cistern in 5 hours
therefore work done by it in 1 hour will be 1/5
now all we need to do to find the total work done by both the taps is to add simply add the fractions 1/4 and 1/5
hence 1/4+ 1/5= (5+4)/20
hence work done by both taps = 9/20
since we need to find the time in which the work is done, we simply take the reciprocal of the above sum.
hence time in which both taps together fill the cistern =20/9 hours
Hope it helps