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 ```a river rises in the Boston mountains at an altitude of 1250 yards and after traveling 150 kilometers the river discharges into a lake at an altitude of 300 meters. What is the overall gradient for the stream in feet per mile. At one point the river is 16 feet deep and 12 meters wide. The water has a velocity here of 4 meters per second, what is the discharge in meters cubed per second?```
 ```Hi carlafaye-ga, This sounds more like an exercise in metric conversion than an exercise in geology! You need to find the overall gradient in "feet per mile", so I'll re-phrase the question in those units: "a river rises in the Boston mountains at an altitude of 3750 feet and after traveling 93.205679 miles the river discharges into a lake at an altitude of 984.25197 feet". The gradient is therefore (3750 - 984.25197) feet / 93.205679 miles, which equals 29.6736 feet per mile. The cross-section of the river is 4.8768 meters (16 feet) times 12 meters, which equals 58.5216 square meters. The discharge is therefore 58.5216 square meters times 4 meters per second, which equals 234.0864 cubic meters per second. Conversion factors used (from the Linux "units" program): One yard equals 3 feet One meter equals 3.2808399 feet One kilometer equals 0.62137119 miles Regards, eiffel-ga```