The question needed to be asked to whichever girl that opens the door is..
"If I ask the other girl whether the red/green box contains 1 million U.S dollars will she say yes?"
If the answer is NO ( whichever girl it is) means the red/green box has the money. If the answer is YES, means the other color(green/red) box has the money.
Explaination.
1) Liar opens the door. Since the other girl always says the truth, and red has the money, other girls answer to it will be a YES, but the liar will negate it, saying NO.
If red doesnt have the money, other girl's answer will be a NO, but liar negates it saying YES.
2) The truthful one opens the door. If red has the money, the liar will obviously answer it as a NO, which the turthful one will mention as a NO.
If red doesnt have the money, the liar will answer as a YES, which truthful one will mention as a YES.
Thus NO to the question means the money is in the same color box as u asked. And a YES means it's in the opposite color box.
very simple
jab ladki door kholay ge to us kay hath main box ho ga main us say poochoon gee kay tumharay hath main kon say colour ka box hai agar wo such bolnay wali ho gee to wo same colour ka jawab day gee aour agar jhoot bolnay wali ho gee to wrong colour ka nam lay gee aour mujhay pata chal jay ga kay wo such bolnay wali hai ya jhoot
kaisaaaaaaaa
main nay theek bataia na
i m sure
i m 100% rite.
girls live in the same house and have both boxes??..what is this yar 
