The sum of two facing page numbers in a book is 145. What are the two page numbers?

Question

The sum of two faving page numbers in a book is 145. What are the two page numbers?

Answer 1

Page numbers are consecutive integers.

n + n + 1 = 145

2n + 1 = 145

2n = 144

n = 72

 

The pages are number 72 (left page) and 73 (right page).

Answer 2

Hi Alyssa.

 

One of the numbers must be just 1 bigger than the other.

 

So if the left page is say, 45 for example, then the right page would need to be 46

 

In "letters", we could say that the left page number was "n" so the right page number must be (n+1).

And we know that  they must add up to 145, so left + right = 145 

 

Putting these together:

 

n + (n+1) = 145

 

n + n + 1 = 145

 

Combine like terms

 

2n + 1 = 145

 

Subtract 1 from both sides

 

2n = 144

 

Divide both sides by 2

 

n = 72

 

So the left side is page # 72, and

the right side page # is 73

 

Checking, does 72 + 73 = 145?  Answer is YES, so this is the correct answer.