Question 795251
Speed of current = x
Speed of boat with current = 4 + x
Speed of boat against current = 4 - x
1 *(4 + x) = 1.5 * (4 - x)
4 + x = 6 - 1.5x
Collect like terms:
x + 1.5x = 6 - 4
2.5x = 2
x = 2/2.5
x = 0.8 mph.
The speed of the current = 0.8 mph
Hope this helps.
:-)