100.75 + 10x \(\leq\) 50
This is how our inequality looks where x represents items cost per bag.
10*x \(\leq\) 42.5
x \(\leq\) 4.25.
Marcus can spend $4.25 at most per bag.
The money he spent on buying bags we can calculate right away because we know how much one bag costs and how many bags he bought.