8. A kayaker spends 2 hours paddling up a
stream from point A to point B, quickly turns
her kayak around, and immediately heads
back downstream. It takes her only 1 hour to
float back down the stream from point B to
point A. If points A and B are 6 miles apart,
what was the kayaker's average rate of
speed in miles per hour?
A. 12 mph
B. 6 mph
C. 4 mph
D. 2 mph

HELP.