Answer:
s/100r
Explanation:
This is fairly simple!
First, make a proportion like s/100 and x/ 1/r
Next we cross multiply that lets us with 100x=s(1/r)
After that, let's simply s(1/r) to s/r
Then we divide it by 100 because it is 100x, that is s/r /100
Finally, we multiply r with 100 to let us have s/100r
I hope you understand, ask any questions in the comments:)