Question

Two pages that face each other in a book have 381 as the sum of their page numbers. What is the number of the page that comes first?

Answer 1

To find the first of two consecutive page numbers that sum to 381, we determined that the first must be even, and through solving the equation, we found it to be page 190.

Step-by-step explanation:

When two pages face each other, one is an even number and the other is odd, since they are printed on the front and back of a single sheet. If their sum is 381, we want to find the lower number. We can deduce that the lower number must be even because books generally start with page 1 on the right side, making the left page (even number) come before the right page (odd number).

Let's call the even page number x, which means that the odd page number would be x+1. Their sum is dictated by the problem:

• x + (x + 1) = 381

Solving for x:

• 2x + 1 = 381
• 2x = 380
• x = 190

Therefore, the page that comes first is page number 190.