As the problem suggests, we must do h = 0, then we must solve the following quadratic equation
![-16t^2+10t+6=0](https://img.qammunity.org/2023/formulas/mathematics/college/jn4jf2kg1bm8q48hmfb0j5qktxctunu6vo.png)
We can simplify it to (divide all terms by 2)
![-8t^2+5t+3=0](https://img.qammunity.org/2023/formulas/mathematics/college/m89x6r7vx9322ujdcophqixayw8lm0l97a.png)
Now we can use the quadratic formula to solve it
![\begin{gathered} t=(-b \pm√(b^2 - 4ac))/(2a) \\ \\ \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/939vf9o5fkxhj2l3thlcc534xjy4u7w0up.png)
Where
a = -8
b = 5
c = 3
Then
![\begin{gathered} t=(-5\pm√(5^2-4\cdot(-8)\cdot3))/(2\cdot(-8)) \\ \\ t=(-5\pm√(25+96))/(-16) \\ \\ t=(5\pm√(121))/(16) \\ \\ t=(5\pm11)/(16) \\ \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/xs081oqvk2x4ges3wehwki95oijks6xysn.png)
Therefore the solutions are
![\begin{gathered} t=(5+11)/(16)=1 \\ \\ t=((5-11))/(16)=(-6)/(16)=-(3)/(8) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/ib7r2iizrdx933p92nn8gbo3fjgg4vtxcn.png)
The only valid solution is t = 1, because we can have negative time, therefore the answer is t = 1
Final answer: