Well, I'm not sure what units "0.5" apply to, but to find the distance he rode, you will need to multiply.
0.5 * 24 = 12.
Barry rode his scooter for a distance of 12 [insert units here].
Hope this helps! Have a great day :)
I believe its 1048576/6561<span />
No. 2/3 is bigger than 5/8 because if you convert them to where the denominator is the same, 5/8= 15/24 and 2/3 is equal to 16/24
Your answer would be, -6ap^3