"You can kick a soccer ball a distance of $28$ $m$ when standing on level ground if the ball is launched at a ${40}^{\circ}$ angle. If you kick the ball in exactly the same way, but are at the foot of a ${15}^{\circ}$ upward slope, what is the horizontal distance traveled by the ball when it hits the ground?"
The answer is $19$ $m$
How do I go about solving this problem?
Using the equation $V_f^2 = V_i^2 + 2ad$, I found the initial velocity to be $23. 426$ $m/s^2$ but I'm not sure where to go from here...