Call the books A, B, C, D.

The three thirds of any book can be represented by the book letter followed by 1, 2 or 3.

Now write down the thirds of the books in a line:

A1 A2 A3 B1 B2 B3 C1 C2 C3 D1 D2 D3

From this picture, where the reading material is split into pairs representing 2/3 of a book or the final 1/3 of a book and the first third of the next, it’s easy to see how many nights it will take him to read all of the books. It will take 6 nights. The same result is obtained by dividing 4 by ⅔=4×3/2=6.

- All categories
- Pre-Algebra Answers 12,288
- Algebra 1 Answers 25,179
- Algebra 2 Answers 10,406
- Geometry Answers 5,145
- Trigonometry Answers 2,632
- Calculus Answers 5,936
- Statistics Answers 3,012
- Word Problem Answers 9,992
- Other Math Topics 6,534

81,124 questions

85,194 answers

2,143 comments

68,587 users