Question

Paddling with the current, a group of kayakers traveled 9 miles in 2 hours. Paddling back, they traveled 4 miles in the same amount of time. What was the speed of the current and the speed of the kayakers in still water?

Answer 1

Answer:

• 3.25 mph and 1.25 mph

Step-by-step explanation:

Let s - speed in still water, c - speed of current.

We have the following equations:

• 2(s + c) = 9
• 2(s - c) = 4

Simplify:

• s + c = 4.5
• s - c = 2

Add up and solve for s:

• 2s = 4.5 + 2
• 2s = 6.5
• s = 6.5/2
• s = 3.25 mph

Find c:

• c = 3.25 - 2 = 1.25 mph

Answer 2

Let speed of water and current be x and y respectively

• 2(x+y)=9=>x+y=4.5--(1)
• 2(x-y)=4=>x-y=2--(2)

Adding

• 2x=6.5
• x=3.25mph

And

• y=4.5-3.25=1.25mph