totally agree with answer above, set tenth digit = a, and the unit digit = b.
10a+b=6b => 2a=b

statement one: a+4=b with the equation above, two equations two variables, so solveable.

statement two: a + b > 10 lets, bring b=2a into the equation, we get a + 2a > 10
so, 3a > 10 which also is a > 3.33.... if both digit is interger, we will try 4 first, a=4, (no other numbers than 4 can be plugged in, since a=5, will be a two digit unit number, which the condition that a and b is both a single digit number is given out in the begining) which will be 48, and 6*unit digit 8 will be 48. answer is out, which is sufficient,