The sum of 2 consecutive integers is at most the difference between nine times the smaller and 5 times the large.

Answer 1

x+y <= 9x-5y
6y <= 8x
3y <= 4x

You might also want to consider

x+y <= |9x-5y|

Answer 2

but the integers are consecutive, so

smaller number --- x
next integer ---- x+1

x + x+1 ≤ 9x - 5(x+1)
2x + 1 ≤ 4x - 5
2x ≥ -6
x ≥ -3

Also consider Steve's other possibility .

Answer 3

It usually helps to read the problem carefully.

Nice work, Reiny