It's that time of the year again - no, not the Christmas holidays, the end-of-term exams! Four Hufflepuff sixth years (Devon, Erinne, Jerome, and Tamara) are going to have a tough week - each of them has two exams every day from Tuesday through Friday of the last week of the term. The students facing the Herbology exam are dreading that one in particular, as word has it that Professor Sprout will be requiring students to extract petals from the Carniverous Chrysanthemum in Greenhouse Four.

Can you determine which students took which exams on which days?

1. Each day, only two exams were given to the sixth years - two of the four students sat for one of the exams, while the other two sat for the other.
   
   
2. Jerome and Erinne never had an exam in common.
   
   
3. Devon sat for his Divination exam on Tuesday, and his Ancient Runes exam on Friday.
   
   
4. Tamara was asked to write an essay on Muggle modes of transportation for her Muggle Studies exam on Wednesday.
   
   
5. The Astronomy exam was held atop the North Tower either two days before or two days after Erinne had to collect Glumbumble Treacle for her Care of Magical Creatures exam.
   
   
6. Jerome and Tamara had the same exams on Tuesday and Friday.
   
   
7. The Arithmancy and Care of Magical Creatures exams were not held on the same day.
   
   
8. Tamara very nearly fell asleep during her History of Magic exam (but luckily a classmate gave her a good kick under the table).
   
   
9. Devon and Erinne took exactly two of their exams together.
   

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Solution:

Since the students took the exams in pairs (clue 1), and Jerome and Tamara had the same exams on Tuesday and Friday, the other pair of students on Tuesday and Friday must have been Devon and Erinne. Tuesday and Friday, then, account for the two times that Devon and Erinne had exams together (clue 9). The two combinations (Jerome/Tamara and Devon/Erinne) for Tuesday and Friday are thus not possibilities for Wednesday or Thursday.

Since Jerome cannot be partnered with Erinne (clue 2), he must have been partnered with Devon for both Wednesday and Thursday, leaving Erinne to partner with Tamara.

Thus, the combinations of students for the week are as follows:

Tuesday: Jerome/Tamara and Devon/Erinne Wednesday: Devon/Jerome and Erinne/Tamara Thursday: Devon/Jerome and Erinne/Tamara Friday: Jerome/Tamara and Devon/Erinne

Devon and Erinne took the Divination exam on Tuesday and the Ancient Runes exam on Friday (clue 3). Erinne and Tamara took the Muggle Studies exam on Wednesday (clue 4). We've thus accounted for three out of four of Erinne's exams. The remaining day, Thursday, thus would be the only possible day for her Care of Magical Creatures exam (clue 5). So Erinne and Tamara took the COMC exam on Thursday.

Since Astronomy has to be either two days before or two days after COMC (clue 5), it has to be Monday, which means it was taken by Jerome and Tamara. We've thus accounted for three out of the four tests that Tamara took (Astronomy on Monday, Muggle Studies on Tuesday, COMC on Wednesday), so Friday is the only remaining day on which she could have taken the History of Magic exam (clue 8).

The only two slots for which we don't have exams, then, are the ones taken by both Devon and Jerome on Wednesday and Thursday. Since the Arithmancy and COMC exams weren't held on the same day (clue 7), Arithmancy must be on Tuesday as COMC is on Wednesday. Thus, Herbology must have been in the only remaining slot left - the test taken by Devon and Jerome on Wednesday.

To sum up:

Tuesday:	Astronomy, taken by Jerome and Tamara
	Divination, taken by Devon and Erinne
Wednesday:	Arithmancy, taken by Devon and Jerome
	Muggle Studies, taken by Erinne and Tamara
Thursday:	Care of Magical Creatures, taken by Erinne and Tamara
	Herbology, taken by Devon and Jerome
Friday:	Ancient Runes, taken by Devon and Erinne
	History of Magic, taken by Jerome and Tamara