Question 483543
Let first number = x
The second is 3 less than twice the first= 3-2x
The third is 6 less than thrice the first= 6-3x

(first#+second#+third#)/3 = Average
[(6-3x)+(3-2x)+x]/3=39
(6-3x+3-2x+x)/3=39
(9-4x)/3=39 (Multiply by 3 both the sides)
9-4x=117
-4x=117-9
-4x=108
-4x/4=108/4=4x/4 (Divide by 4 both sides)
-x=27
x=-27

the second is 3 less than twice the first= 3-2x = 3-2(-27)=3+54=57
third is 6 less than thrice the first= 6-3x=6-3(-27)=6+81=87

-27,57,87