Can't Fool the Science Teacher!

A Senior Year Chemistry Class was taught at Drew College for many years by Mr. Radowicz. One year, two seniors took the class and did pretty well on all the quizzes and mid-terms--so much so that going into the final, they each had a solid A. These two friends were so confident going into the final that the weekend before the Final Exam on Monday, they decided to go and celebrate their achievement with some friends.

They did this and had a great time. However, with their hangovers and tiredness, they overslept all day Sunday and didn't make it to school on time on Monday morning. Rather than taking the final then, they found Mr. Radowicz after the final and explained to him how they missed the final. They told him they were on their way to school that morning, but had a flat tire on the way and didn't have a spare. They couldn't fix it for a long time and were late getting to school.

Radowicz thought this over and agreed that they could take the final the following day. The two guys, elated and relieved, studied that night and went in the next day at the time that they had been told. Radowicz placed them in separate rooms and handed each of them a test booklet. He told them to begin.

They looked at the first problem which was something simple about mixtures and solutions; it was worth 10 points. "Cool," they thought, "this is going to be an easy final". They then turned the page. They were unprepared, however, for what they saw on it. The question contained only two words: (90 points) Which tire?