Answer:
The right solution is "24.39 per sec".
Explanation:
According to the question,
⇒ 
The time will be:
⇒ 
hence,
⇒ 
Answer choice C is a benefit of coal; all the others are negatives.
Feel free to ask me more questions; I'm happy to help. (Don't forget Brainliest!)
A) use v=u+at for both
First section, v=27, u=0, a=2.4. You should get 11seconds.
Second section, v=0, u=27, a=-1.3. You should get 21seconds.
This means that the total time is 22seconds.
b) You can either use s=ut+0.5at^2 or v^2=u^2+2as. Personally, I would use the second one as you are not relying on your previous answer.
First section, v=27, u=0, a=2.4. You should get 152m.
Second section, v=0, u=27, a=-1.3. You should get 280m.
This makes your overall displacement 432m.
