Where did two dollars go?? [duplicate]

One of my school friends gave me this sum.Its basically a story formated into a sum

STORY

There were 3 friends. They each gave 20 dollars to buy a radio. They bought the radio for 60 dollar. Later the shopkeeper saw that the cost of the radio was 50 dollar. So he went to the friends to return 10 dollar. On the way (of returning) he thought that 10 dollar can't be divided among 3 friends. So he himself took 4 dollar and rest 6 dollar was divided among three friends. thus each friend got 2 dollar.

SUM

Initially the shop keeper had 60 dollar.

And each friend finally gave 18*3=54 dollars and the shopkeeper himself took 4 dollar. thus total 58 dollar.

THEN WHERE DID EXTRA 2 DOLLAR GO?????

I tried it in many ways but still could not. can any one help me out.

marked as duplicate by Henry, Ian Miller, Alex M., Harish Chandra Rajpoot, Community♦Jan 9 '16 at 12:42

• $\$54 - \$4 = \$50$and$\$54+3\times \$2=\$60$ – Henry Jan 9 '16 at 10:56
It's not a total of 58 dollars. The shopkeeper is keeping 4 dollars, so instead of the friends paying \$50 for the radio they have paid \$54 after the shopkeeper returns some money.
No you have interpreted wrongly see the shopkeeper has total $54$ dollars not $58$ so $54+2(each)=60$ each got $2$ again. What you have done is radio costs $54$ and top of that shopkeeper takes $4$ dollars which is wrong so two dollars went nowhere