SOLUTION: The sum of three numbers is 40. The second number is twice the first number. The sum of the first two numbers is 2 less than the third number. What are the three numbers?

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Question 1108660: The sum of three numbers is 40. The second number is twice the first number. The sum of the first two numbers is 2 less than the third number. What are the three numbers?
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
system%28x%2By%2Bz=40%2Cy%2Fx=2%2Cx%2By=z-2%29

Substitute for x+y.
system%28z-2%2Bz=40%2Cy=2x%29

2z=42
highlight%28z=21%29

-
system%28y=2x%2Cx%2By=19%29
x%2B2x=19
3x=19
highlight%28x=19%2F3%29
-
highlight%28y=38%2F3%29


CHECK
19/3+38/3+21=40
19%2B21
40=40
-
%2838%2F3%29%2F%2819%2F3%29=2-----yes
-
19%2F3%2B38%2F3=21-2
57%2F3=19
19=19------yes