Then the water velocity is (x-y)/2km/ hour.

Countable equation 6X=8Y

X=4Y/3。

So the water flow speed is y/6 km/h.

The whole journey is 8Y kilometers.

Therefore, it takes 8Y divided by Y/6=48 hours for a ship to drift from port A to port B by using the current speed.

Another method

It takes x hours for a ship to drift from port A to port B at the current speed.

According to the meaning of the question, (1/6)-(1/x) = (1/8)+(1/x)

Solve the equation and get x=48.

X=48 is the solution of the equation.

It will take 48 hours for the ship to drift from port A to port B at the current speed.