Going down the river a boat went 13 km/h. going up the river it only 1 km/h. find the speed of the boat in still water and the speed of the current.

This question looks really tricky, but it's actually just describing a system of equations. We have the equation for the speed of the boat with the current and the speed of the boat against the current. Call the boat speed b and the current speed c:



Then




So the boat's speed is 7 km/h. Find the current's speed by plugging the boat speed back into one of the original equations:



The current's speed is 6 km/h.

Y=-2x-6 is the answer