Respuesta :
4 miles = 1 hour upstream
6 miles = 1 hour downstream
In seven hours: 4mi (7hr) = 28mi upstream + 6mi (7hr) = 42mi downstream
Added together: 28+42=70mi total.
6 miles = 1 hour downstream
In seven hours: 4mi (7hr) = 28mi upstream + 6mi (7hr) = 42mi downstream
Added together: 28+42=70mi total.
distance up = distance down stream.distance = speed x timeso you have 2 equationsd= 4 td= 6 (7-t)where t is the time going up stream, and 7-t is the time going downstream.(because time up plus time down is 7)set the equations equal. solve for t. use t to find d.