1. The problem statement, all variables and given/known data A hot air balloon is ascending straight up at a constant speed of 8.10 m/s. When the balloon is 13.0 m above the ground, a gun fires a pellet straight up from ground level with an initial speed of 28.0 m/s. Along the paths of the balloon and the pellet, there are two places where each of them has the same altitude at the same time. How far above ground level are these places? Enter the answers in the ascending order. 2. Relevant equations Kinematic equations: V = Vo + at X - Xo = Vot + .5at2 v2 = vo2 + 2a(X - Xo) X - Xo = .5(Vo + V)t 3. The attempt at a solution I tried using the X - xo = Vot + .5at^2 equation for both the balloon and the bullet to get two variables, delta x and t, and then solving for each. But I've tried it several times and I keep getting funky answers (like negative values for t) and I don't know what I'm doing wrong.