You can set it up like this:
x + (3x - 5) = 119
Add 5 to both sides:
x + 3x = 124
Combine like terms:
4x = 124
Divide both sides by 4:
x = 31
So, one number is 31, and since the other is 5 less than three times that number, it's 31(3) - 5 = 88. To check, add the two (31 and 88) together, and sure enough, the answer is 119!
Hope this helped!! xx