Question

Alvin wants to know what his average paddling rate was for a canoe trip to a campsite. On the way there it took him 7 hours against a river current of 5 km/ hr. On the way back, the same distance took him 5 hours with the same 5 km/hr current.

Answer 1

Explanation:

Let Alvin's speed = x

The distance is the same both ways.

d = (x + 5)*5 coming back

d = (x - 5) * 7 going there.

(x +5)*5 = (x - 5)*7 Remove the brackets

5x + 25 = 7x - 35 Subtract 5x from both sides.

25 = 7x - 5x - 35 Combine

25 = 2x - 35 Add 35 to both sides

25 + 35 = 2x Combine

60 = 2x Divide by 12

60/2 = x

x = 30

His paddling speed was 30