Hi all, I need help to solve a homework question. I hope you guys won't mind and I just need a hint (or two). Question is:

A child in danger of drowning in a river is being carried downstream by a current that flows uniformly with a speed of 2.0 m/s. The child is 200 m from the shore and 1500 m upstream of the boat dock from which the rescue team sets out. If their boat speed is 8.0 m/s with respect to the water, at what angle from the shore should the pilot leave the shore to go directly to the child?

I think of this as a river flowing north/south with the boat dock 1500 m south of the child on the same bank that the question says is 200 m from the child. The rescue boat is running north approaching the child who is flowing downstream (south) with the shoreline being the y-axis and the breadth of the river being the x-axis. The child moves so the theta is increasing as time passes but I'm not sure how to solve for it.

I was thinking solve for the time when they are equal with r=d/t but that only got me with the fact that for every unit of distance the child travels, the boat does 4x more. Am I right by saying that the resultant vector created by the velocity of the boat is 8? And the x-component is 8*sin(theta) and y-component is 8*cos(theta)? But now I'm thinking, what if instead of 8*cos(theta) it's actually 8*cos(theta)-2? That way the child moving is subtracted from the moving boat.

I'm not sure what to do, could anyone do me a favor and help me out?