Consecutive integers

Question

The left and right page numbers of an open book are 2 consecutive integers whose sum is 161. Find these page numbers. 

Answer 1

n + n + 1 = 161              combine like terms

2n + 1 = 161                   subtract 1 from both sides

2n = 160                         divide both sides by 2

n = 80

 

The page numbers are 80 and 81.