Question

Sun, a kayaker, paddles 8 miles upstream (against the current) in 2 hours. Returning to her original location, she paddles downstream (with the current) the same distance in 1 hour. The equations represent x, the paddling speed, and y, the speed of the current.2(x – y) = a

Answer 1

a = 8, b = 1

or,

a & d

Answer 2

We calculate both velocities:
upstream 8 miles in 2 hours = 4 miles / hour
downstream 8 miles in 1 hour = 8 miles / hour

ps -stream speed = 4 mph
ps + stream speed = 8 mph
Adding both equations
2 ps = 12 mph
paddling speed = 6 mph
stream speed = 2 mph