<span>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</span> <span>4x+(x+100)-500=0 </span><span>5x=400</span> <span>x=80 </span><span>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 </span> Hope this helps! If you have any questions just ask!