Converting horizontal speed to vertical speed

Hello I am having some difficulty solving this problem. Any help would be greatly appreciated.

For 1989 and 1990 Dave Johnson had the highest decathlon score in the

world. When Johnson reached a speed of 32ft/sec on the pole vault runway,

his height above the ground t seconds after leaving the ground was given by

h=-16t+32t. (The elasticity of the pole converts the horizontal speed into

vertical speed.) Find the value of t for which his height was 12 ft.

Use the information from the above problem to determine how long Johnson

was in the air. For how long was he more than 14 ft in the air?