Question 636600
Let x = the second number
  x-6 = the first number
3(x-6)= the third number

The sum of three numbers is 111.
x-6+x+3(x-6)=111
 x-6+x+3x-18=111 
       5x-24=111
          5x=135
           x=27

Substitute x for 27
27-6=21
3(27-6)=63

The numbers are 21,27 and 63.