4) 4m, 18, and g
5) 4n means 4xn
The first choice can be any one of the 8 side dishes.
For each of these . . .
The 2nd choice can be any one of the remaining 7.
Total number of ways to pick 2 out of 8 = (8 x 7) = 56 ways .
BUT ...
That doesn't mean you can get 56 different sets of 2 side dishes.
For each different pair, there are 2 ways to choose them . . .
(first A then B), and (first B then A). Either way, you wind up with (A and B).
So yes, there are 56 different 'WAYS' to choose 2 out of 8.
But there are only 28 different possible results, and 2 'ways'
to get each result.
In order to answer this question let's suppose,
Joe is x miles from the beginning and y miles from the end. These assumptions are necessary to answer further:
Now,
x=2y
x+y=30
plugging in x=2y in the above equation
2y+y=30
3y=30
y=10
Hence, according to our calculations, Joe has to hike 10 miles further