Mathematics
NULL
Medium
Question
One tap can fill a cistern in 2 hours and another can empty it in 3 hours. How long will they take to fill the cistern if both are opened?
A
5 Hours
B
6 Hours
✓ Official correct answer
C
7 Hours
D
8 Hours
Community credibility
Registered members can vote for the answer they believe is correct today and explain why. If the facts change after an election or news event, suggest a new option so others can vote it up.
A
5 Hours
No member explanations yet for this option.
B
6 Hours
No member explanations yet for this option.
C
7 Hours
No member explanations yet for this option.
D
8 Hours
No member explanations yet for this option.
Explanation
Net rate = 1/2 − 1/3 = 1/6. Time = 6 hours.