Step-by-step explanation:
Rate × time = distance
If x is the rate of the boat and y is the rate of the water:
(x − y) × 4 = 128
(x + y) × 2 = 128
Simplifying:
x − y = 32
x + y = 64
Solve with elimination (add the equations together):
2x = 96
x = 48
y = 16
The speed of the boat is 48 km/hr and the speed of the water is 16 km/hr.
