If the difference of two consecutive numbers is 15 and the greater of them is X then the smaller number is

Answer 1

It's not possible for the difference of two consecutive numbers to be 15, by definition of 'consecutive', the difference is one

If, however, the word 'sum' is supposed to be at that place, then the numbers are 7 and 8

Answer 2

or, if we eliminate the "consecutive" then we have

If the difference of two numbers is 15 and the greater of them is X then the smaller number is X-15