7.5 quarts of olive oil remain.
Explanation:Let
q = quarts of olive oil remain
25% of olive oil remains means that 75% has been used.
2212 quarts = 22.5 quarts used
22.5.75=q.25
Multiply both sides by .25 to isolate q.
22.5.75(.25)=q.25(.25)
5.625.75=q
7.5=q