Question 483543: the average of 3 numbers is 39. the second is 3 less than twice the first and the third is 6 less than thrice the first. find the 3 numbers. Found 2 solutions by Maths68, MathTherapy:Answer by Maths68(1474) (Show Source):
You can put this solution on YOUR website! 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
You can put this solution on YOUR website! the average of 3 numbers is 39. the second is 3 less than twice the first and the third is 6 less than thrice the first. find the 3 numbers.
Let first number be F
We can then say that:
F, or first = F
Second = 2F – 3
Third = 3F - 6
Now, since the average of the numbers is 39, we than have:
6F – 9 = 117 ---- Cross-multiplying
6F = 126
F =
F, or first number =
Then second = 2(21) – 3 = 42 – 3 =
Third = 3(21) – 6 = 63 – 6 =
