The characters are shown speaking on mobiles near Pangong Tso (about 150Kms ahead of Leh) towards the end of the movie. There is no mobile coverage in the area. The last being at Tangtse (about 100Kms from Leh).
Farhan Qureshi: Today my respect for that idiot shot up. Most of us went to college just for a degree. No degree meant no plum job, no pretty wife, no credit card, no social status. But none of this mattered to him, he was in college for the joy of learning, he never cared if he was first or last.
About 20% of the plot and characters of 3 Idiots was inspired from Indian writer Chetan Bhagat's "Five Point Someone". Despite there was no such thing taken from the book, the writer was given a special thanks when the credit rolls in the end.