Answer:
![\boxed {\tt 230.769231 \ seconds}](https://img.qammunity.org/2021/formulas/physics/high-school/ok96nmz9elr22ojuh1hi910km15714d16h.png)
Step-by-step explanation:
Time can be found by dividing the distance by the speed.
![t=(d)/(s)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/dr21dc8riffitfyo4az5x17f46kxna2uxs.png)
The distance is 9,000 meters and the speed is 39 meters per second.
![d= 9,000 \ s\\s=39 \ m/s](https://img.qammunity.org/2021/formulas/physics/high-school/sklhs8zps6kvvxmlf3wtayx8l1j1g1mb08.png)
Substitute the values into the formula.
![t=(9,000 \ m)/(39 \ m/s)](https://img.qammunity.org/2021/formulas/physics/high-school/7v45lv12sluf4anxy0cnlmvrjh1u7fvcl7.png)
Divide. Note that the meters, or "m" will cancel out.
![t=(9,000)/(39 \ s)](https://img.qammunity.org/2021/formulas/physics/high-school/58emabqswj1ywg0ngusgm2ox96bmgwzl4v.png)
![t=230.769231 \ s](https://img.qammunity.org/2021/formulas/physics/high-school/6fhabxm0p1yl05md0kiysid68jcfipby0z.png)
It takes 230.769231 seconds for the truck to travel 9,000 meters at 39 meters per second.