Question 319016
Each page on a book has a page number. You are asked to find the 3 consecutive pages whose page number sums to 60.
Let the lowest page number be given by x.
Then the next consecutive page is {{{x+1}}}
And the next one after that is {{{x+2}}}
You are told the three page numbers sum to 60. So
{{{x + (x+1) + (x+2) = 60}}}
{{{3x + 3 = 60}}}
{{{3x = 57}}}
{{{x = 19}}}
Then the three pages are page 19, page 20 and page 21.

Get it?