C(25,10)= 3268760
P(25,10)=11861676288000
hope it helps but these are very big numbers :d
I believe you just multiply the two numbers together and get 2.665
It has to do with the number of dimensions you have in the figure. For example, in a square you have 2 dimensions, length and width. Since you have only two you use units^2. In a cube, you have 3 dimensions, length, width and height, which is where you get the units^3.
If the troops hike 7km/2hr (read 7 kilometers per 2 hours), then to find how far they'd hike 4hr, just find multiply the top and bottom by 2. We do this because we found that to get from 2 to 4, we multiply by 2. And since this is a rate, we multiply the top by this value as well, so 7x2=14km