A paddling canoeist took 2 h to travel 12 km down a river, with the current. It took 4 h to do the return trip up the river, against the current. What was the speed of the current

Guest Feb 4, 2020

#1**+1 **

12 / 2 = 6 km/h - his speed with the current

12 / 4 = 3 km/h - his speed against the current.

[6 - 3 ] / 2 =1.5 km/h - the speed of the current.

Guest Feb 4, 2020

#2**+1 **

Call the current spped, C

Call the speed of the boat in still water, R

Effective rate with current = R + C

Effective rate against the current = [ R - C ]

So we have that distamce / rate = time...so...

12/ [ R + C] = 2 12 /[ R - C] = 4

12 = 2 [ R + C] 12 = 4 [ R - C]

6 = R + C 3 = R - C

Add the last two equations

9 = 2R

4.5 = R

And

6 = R + C

6 = 4.5 + C

1.5 = C

CPhill Feb 4, 2020