The chai vala

As you all know i often travel, so one day again i was travelling in train with my two friends.
 One was busy sleeping and the other with his songs on his headphones, i was also bored sitting alone without talks so i decided to hear songs, for that i grabbed my bag removed headphones and was about to start the music, where i heard a noise of conversation of chai vala near me with a men who wanted an extra cup but the chai vala denied. The answer i also wanted to know.
 ‎ The conversation didn't continued longer...  That conversation grabed the attention one of my friend he also wanted to know.
 ‎That question made him so curios that he asked the chai vala that why didn't he gave an extra cup.
 ‎ The reply was too good that i didn't even imagined that way, he replied that "one cup cost you 1₹ but for him one cup cost 10₹" Yes, i also didnt understood the logic then he again interrupted that initially he sells one cup plus chai in 10₹ if he gives one cup for 1₹ then in what he would sell the left chai because the cup is gone, so intially he would be in loss of 9₹, it was good answer i didnt even thought it that way

Did u thought that way....... ??
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