Answer:
25.45%
Explanation:
If we have two values a and b, then the percent difference is defined as
[tex]\frac{|a-b|}{(a+b)/2}\times100\%[/tex]
In other words, the percent difference is defined as the absolute value of the difference divided by their average.
Now in our case, the two numbers we have are 155 mph and 120 mph. Now the average of 155 and 120 is
[tex]\frac{120+155}{2}=135[/tex]
The difference between the two numbers is
[tex]|155-120|=35[/tex]
Therefore, the percentage difference is
[tex]\frac{|155-120|}{(120+155)/2}\times100\%=\frac{35}{135}\times100\%[/tex]
which we evaluate to get
[tex]\frac{35}{135}\times100\%=\boxed{25.5\%.}[/tex]
which is our answer!
