Question 214849
Let the first number be x, then the second number is 5x, and the third number is x+100.  The sum of these three numbers is 415.
x+5x+(x+100) = 415 Combine like-terms.
7x+100 = 415 Subtract 100 from both sides.
7x = 315 Divide both sides by 7.
x = 45
5x = 225
x+100 = 145.
Check:
45+225+145 = 415