please help me if u do ill give to the best brainliest :)

Step-by-step explanation:
t in 1200m:
[tex]t = \frac{4500}{x} \\ x = 1200 \\ t = 4500 \div 1200 = 3.75[/tex]
t in 3750:
[tex]t = \frac{4500}{x} \\ x = 3750 \\ t = 4000 \div 3750 = 0.12[/tex]
difference is:
3.75-0.12 = 3.63