SOLUTION: On 5th June 2011, 124 mm of rainfall was recorded over an area of 28 km2. If the rainwater falling onto the area was drained through two channels each with a cross-sectional area o

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Question 1014716: On 5th June 2011, 124 mm of rainfall was recorded over an area of 28 km2. If the rainwater falling onto the area was drained through two channels each with a cross-sectional area of 18m2 at a rate of 26.4 m/s, find the time, to the nearest minute, required for the channes to drain off the rain.
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Find the volume of water first, converting to meters for consistent units.
V=A%2At
V=28%281000%29%281000%29%2A%28124%2F1000%29
V=3472000m%5E3
The volume flow rate (remember there are two drains) was then,
VFR=2%2AV%5Bx%5D%2AA%2As
VFR=2%2A26.4%2A18%2As
VFR=950.4%2As
where s is the number of seconds to drain,
3472000=950.4s
s=3653
Or in minutes,
m=3653%2F60
m=60.88
or 61 minutes to the nearest minute,