Answer:2t
Step-by-step explanation:
Given
Jason throwing watermelon at speed v and it spend t time in air
time to reach max height
![v_f=u_i+at'](https://img.qammunity.org/2020/formulas/physics/college/m8wketfrzh3sjqltp78rkah68h5h803iws.png)
0=v-gt'
![t'=(v)/(g)](https://img.qammunity.org/2020/formulas/physics/college/h9l2wxg1bhxxvecorxm95nu9gkgkjx56sr.png)
and time to reach bottom is also t'
t=2t'
![t=2(v)/(g)](https://img.qammunity.org/2020/formulas/physics/college/b933sjtgzj49udafh807o47ll3e5j27eqf.png)
For guy throws his watermelon at speed 2v
So total time in air will be
![t''=2(2v)/(g)](https://img.qammunity.org/2020/formulas/physics/college/22e7395v5x2now9tuvbnx8og5mz2iobb7t.png)
![t''=4(v)/(g)](https://img.qammunity.org/2020/formulas/physics/college/oee3jihkar789c2xisctnkukxl3dt9x064.png)
t''=2t