Thanks Angela for pulling me out and for the explanation. I was thinking whether doubling up the rope doubled the pulling force which is mechanically not possible. The cars are the same, the force exerted is the same, the only difference the rope was doubled and made shorter. The 1st attempt with the longer single rope didn't serve the purpose whereas the 2nd attempt was successful. From that time I was trying to understand the mechanics behind this and now I got the perfect answer. It was not doubling up the force but shortening the rope gave you much better maneuverability to pull and helped in the successful recovery.
I will remember this lesson for all my offroading days.
THANK YOU @Foxtrot Oscar