Answer:
The difference between the distances they walked is 600 meters.
Step-by-step explanation:
Let's calculate the distance traveled by Nichol and Sakura with the following equation:

Where:
v: is the speed
t: is the time
The distance traveled by Nichol is:

And the distance traveled by Sakura is:

Hence, the difference between the distances they walked is:

Sakura traveled 600 meters more than Nichol.
Therefore, the difference between the distances they walked is 600 meters.
I hope it helps you!
I think it’s 4 m because diameter is 2r
Spain = 140
Italy = 40
France = 60
U.S.A = 120
total = 18,000,000
Spain : 140/360 = 39%.....0.39(18,000,000) = 7,020,000
Italy : 40/360 = 11%....0.11(18,000,000) = 1,980,000
France : 60/360 = 17%....0.17(18,000,000) = 3,060,000
U.S.A : 120/360 = 33%...0.33(18,000,000) = 5,940,000
It would be a x/n = n √a^x
Hope this helps