Question

A book of 100 pages is flipped open. The sum of the facing numbers can be divided by 5. The quotient is a product of 3 and 7. What are the facing page numbers

Answer 1

so, the sum of the pages numbers is a multiple of 3,5,7 = 105

If the lower-numbered page is x, then
x + x+1 = 105
x = 52
The pages are 52,53