Incorrect. You need to find t when $\displaystyle{16}=-{16}{{t}}^{{2}}+{52}{t}+{4}\usepackage{cmbright}\Huge\$ . Rewrite so that the right side is 0: $\displaystyle{16}{{t}}^{{2}}-{52}{t}+{12}={0}\usepackage{cmbright}\Huge\$ . Divide both sides by 4 to simplify. Then use the Quadratic Formula. There are two solutions: the smaller number is when the ball is going up, and the larger number is when the ball is coming down.