Mathematics
NULL
Medium
Question
Three pipes fill a tank: the first two together take as long as the third alone. The second is 5 hours faster than the first and 4 hours slower than the third. Time required by the first pipe?
A
6 hrs
B
10 hrs
C
15 hrs
✓ Official correct answer
D
30 hrs
Community credibility
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A
6 hrs
No member explanations yet for this option.
B
10 hrs
No member explanations yet for this option.
C
15 hrs
No member explanations yet for this option.
D
30 hrs
No member explanations yet for this option.
Explanation
Let first take x hours: 1/x + 1/(x−5) = 1/(x−9). Solving gives x = 15 hours.