Answer:
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