Hello from MrBillDoesMath!
Answer:
5, 10, 0
Discussion:
Let "f" be the first number. Then the questions tells us that
f + 2f + (f-5) = 15 =>
f + 2f + f - 5 = 15 => add 5 to both sides
4f = 5+ 15 = 20 => divide both sides by 4
f = 20/4 = 5
The numbers as
f: 5
2f: 10
(f-5): 0
Thank you,
MrB