Let us say, the number is "a"
one less than "a" is ... well a - 1
2/5 of that will be... well, 2/5 * ( a - 1)
one more than "a" is... well a + 1
3/5 of that is.. hmmm 3/5 * (a + 1)
now, we're told that, the first expression is "less than" the second one, thus
solve for "a", or make it "x" if you wish, same thing anyway
one less than "a" is ... well a - 1
2/5 of that will be... well, 2/5 * ( a - 1)
one more than "a" is... well a + 1
3/5 of that is.. hmmm 3/5 * (a + 1)
now, we're told that, the first expression is "less than" the second one, thus
solve for "a", or make it "x" if you wish, same thing anyway