Please! I need help with this one..!?

Question

Oscar, Dodong,and Jimmy are three friends. Their last names are Santos, Paterno and Ramos, but necessarily in that order.
They all spent shopping one Saturday. Oscar spent exactly twicw as much as Dodong; and Dodong spent exactly twice as much as Jimmy. Santos spent exactly P12.65 more than Ramos.
What is each person's full name?

Answer 1

I'm not sure what it means when I read "P12.65". I will assume it means dollars (or perhaps British pounds?). I will use just the first letter of the names, except for Oscar I will use "C"

We have: 2J = D, and 2D = C
So we also have 4J = C
And we are told that R+ 12.65 = S.

Now there are only 6 ways to pair up the names, from least spending to most:
(1) JR, DS, CP
(2) JR, DP, CS
(3) JS, DP, CR <-- Not possible, because we need R < S
(4) JS, DR, CP <-- Not possible, because we need R < S
(5) JP, DS, CR <-- Not possible, because we need R < S
(6) JP, DR, CS

We can work out that #2 is not possible, because the difference between J and C is a multiple of 3, but 12.65 is not a multiple of 3.

We can work out that #6 is not possible, because the difference between D and C is a multiple of 2, but 12.65 is not a multiple of 2.

Therefore, we are left with Jimmy Ramos (12.65), Dodong Santos (25.30), and Oscar Paterno (50.60).

Answer 2

We know that they spent money as follows:
Jimmy (x) < Dodong (2x) < Oscar (4x)

We also know that Santos spent P12.65 more than Ramos.

Jimmy can't be Santos because he spent the least. And Oscar can't be Santos. That's because Dodong has to then spend P12.65 and then Jimmy would spend a fractional amount of P6.325. Because it says "exactly twice" this can't be the case. Nor could Ramos be Jimmy, because that would require 3x = P12.65 or x = P4.21667.

So the answer is that Dodong is Santos. From there it follows that Jimmy is Ramos. By process of elimination, Oscar is Paterno.

Final answer is:
Jimmy Ramos (spent P12.65)
Dodong Santos (spent P25.30)
Oscar Paterno (spent P50.60)

Answer 3

Are these guys Filipinos?