Lupe can ride her bike at a rate of 20 mph when there is no wind. On one particular day, she rode 2 miles against the wind and noticed that it took her the same amount of time as it did to ride 3 miles with the wind. How fast was the wind blowing that day?
time = 3 miles / (20 mph - wind velocity)
time = 2 miles / (20 mph + wind velocity)
3 miles / (20 mph + wind velocity) = 2 miles / (20 mph - wind velocity)
3/2 = (20 mph + wind velocity) / (20 mph - wind velocity)
1.5 = (20 mph + wv) / (20 mph -wv)
30 mph -1.5wv = 20 mph -wv
10 mph = 2.5 wv
wind velocity = 4 mph