Cassius drives his boat upstream for

Question

30 minutes. It takes him
15 minutes to return downstream. His speed going upstream is two miles per hour slower than his speed going down stream. Find his upstream and downstream speed.

Answer 1

let the downstream speed by x mph
then the upstream speed is x-2 mph

let the distance gone either way be d miles
time to go upstream = d/(x-2)
time to go downstream = d/x

but the time to go upstream is twice that of going downstream, 30 min vs 15 min

d/(x-2) = 2d/x
divide out the d
1/(x-2) = 2/x
2x-4=x
x = 4

His speed downstream is 4 mph and his upstream speed is 2 mph

Answer 2

Julian rides his bike uphill for 45 minutes, then turns around and rides back downhill. It takes him 15 minutes to get back to where he started. His uphill speed is 3.2 miles per hour slower than his downhill speed. Find Julian’s uphill and downhill speed.

Answer 3

Downstream 9 upstream 6