Quantitative Reasoning

Gaby, Dmitri, and Marat play a game of poker. At the end of the game, Gaby has 12 more dollars than Dimtri, but only one half of what Marat has. If each player brought 20 dollars to the game, what were Gaby's total dollar winnings?

A) -6
B) -2
C) 2
D) 18
E) 24

Dmitir (D)- D
Gaby (G)= D + 12
Marat (M)= 2 (D +12)


4D+ 36= 60
4D=24
D=6

G=D +12= 6+12= 18.

However, answer is B (-2)

Any ideas?