Natalie flipped her book to the middle. The sum of the two facing page numbers is 231.
- What are the two page numbers? Give your answer in this format. (Eg 1, 2)
- How many pages are there in the book?
(a)
Smaller page number = 1 u
Bigger page number = 1 u + 1
Sum of the two facing page numbers
= 1 u + 1 u + 1
= 2 u + 1
2 u + 1 = 231
2 u = 231 - 1
2 u = 230
1 u = 230 ÷ 2 = 115
Smaller page number
= 1 u
= 115
Bigger page number
= 1 u + 1
= 115 + 1
= 116
The two page numbers are 115 and 116.
(b)
Since Natalie flipped her book to the middle, the number of pages on the left side and the right side of the book is the same.
Total number of pages in the book
= 115 + 115
= 230
Answer(s): (a) 115, 116; (b) 230