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: [tex]b+c=13[/tex] [tex]b-c=1[/tex]
Then [tex](b+c)+(b-c)=13+1[/tex] [tex]2b=14[/tex] [tex]b=7[/tex]
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: [tex]7+c=13[/tex] [tex]c=6[/tex]
