Answer:
4 mph
Step-by-step explanation:
Givens
Current = c = 2 mph
Alberta = r = ?
d = 2 mph upstream
d1 = 6 mph downstream
Formula
d = r * t
The time is the same so the formula becomes d/r = t
2/(r - 2) = 6/(r + 2)
Solution
Cross Multiply
2*(r + 2) = 6*(r - 2)
2r + 4 = 6r - 12 Subtract 2r from both sides
4 = 6r - 2r - 12 Combine the right.
4 = 4r - 12 Add 12 to both sides.
4 + 12 = 4r
16 = 4r Divide by 4
16/4 = 4r/4
r = 4
Alberta's rate of travel is 4 mph
