Answer:
7/3 mph
Step-by-step explanation:
knowing that:
distance traveled = velocity * time - velocity of the water * time
4 = v1 * 1.5 + v2 * 1.5
4 = v1 * 2 - v2 * 2
solve the system in any way you want,
v1 = 7/3 miles per hour
v2 = 1/3 miles per hour
