Riddle (simple arithmetic problem/illusion)
three girls have a friend 60 rupees and asked her to buy them a kilo of mangoes each from the market. the mangoes cost 55 rupees. to make it easy to divide the balance of 5 rupees, the friend kept 2 rupees and returned 1 rupee each to the the three girls.thus,the girls spend 19 rupees each and a total of 57 rupees.the friend kept 2 rupees,which makes the total 59 rupees. what happend to remaining 1 rupee?