because p = the number of shirts pedro can buy without pushing $70,
10.01p is the cost of the shirts alone.
For any number of shirts, there is a $9.94 shipping price, which we add onto what we have so far:
10.01p+9.94
because pedro can spend "no more than $70", we will use a less than or equal to inequality symbol.

If we want to simplify that to find what p is, then we subtract 9.94 from both sides of the inequality:

now we divide both sides by 10.01 and we get

And if it needs to be precise, we can do

that shows that p is not a negative number