Sarah flipped her book to the middle. The sum of the two facing page numbers is 243.
- 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 = 243
2 u = 243 - 1
2 u = 242
1 u = 242 ÷ 2 = 121
Smaller page number
= 1 u
= 121
Bigger page number
= 1 u + 1
= 121 + 1
= 122
The two page numbers are 121 and 122.
(b)
Since Sarah 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
= 121 + 121
= 242
Answer(s): (a) 121, 122; (b) 242