One number is 3 times a first number. a third number is 100 more than the first number. if the sum of the three numbers is 500, find the numbers

Let the first number be x.
Then the second number is 3x.
Then the third number is (x+100).
Sum of the numbers=500

x+3x+(x+100)=500
4x+(x+100)-500=0
5x=400
x=80
The first number is 80.
The second number is 240.
The third number is 180.

We can check by adding all three of those numbers together: 80+240+180 = 500

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