a drainage basin bordering the sea has an area of 7500 km2 . the average precipitation for this drainage basin is 900 mm year-1 . the average surface water flow at the outlet of the drainage basin equals 22.5 × 108 m3 year-1 . the average groundwater flow to the sea is 100 mm year-1 . the averages are determined for 30 hydrological years.
a. draw up the water balance.
b. determine the average actual evaporation in mm year-1 and m3 year-1

x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x

step-by-step explanation:

last month maria hiked the 5-mile mountain trail a number of times and she hiked the 10-mile canal trail several times. let x represent the number of times she hiked the 5-mile trail, and let y represent the number of times she hiked the 10-mile trail. if she hiked a total of 90 miles, which equation can be used to find the number of times maria hiked each trail? x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x

y=x+9

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step-by-step explanation: