Uncle Phrank's Math Riddle

[Agent Phrank]

Seller sells hat that costs 10 roubles. A buyer comes, measures it and agrees to take, but he has only 25 rubles banknote. Seller sends the boy with these 25 roubles to the neighbor to exchange. Boy returns and gives 10 + 10 + 5. The seller gives the hat and 15 rubles. After some time, a neighbor comes in and says that 25 roubles were fake and asks to give her money. So seller climbs to the cashier and returns her money.

How many roubles was the seller fooled for?

 

[giostep]

35 roubles and a hat...
Gave the Boy 10 roubles and a Hat and recieved 15 Fakes
Gave the Lady 25 roubles, even though she didnt give him a dime...

 

[Uzumaki Macho]

What's a rouble?

 

[CrimsonReaper]

Do i look like a math genius.I suck at it XD

 

[Agent Phrank]

35 roubles and a hat...
Gave the Boy 10 roubles and a Hat and recieved 15 Fakes
Gave the Lady 25 roubles, even though she didnt give him a dime...

Close, yet so far.

 

[Pumpkin Ninja]

The seller was fooled for 25 roubles.

 

[TheUnbiasedOne]

50 Roubles

 

[7th Biggest OP Fan]

Zero. How was Seller fooled?

 

[Rokudaime Hokage Naruto]

15 roubles and a hat

 

[Artesia]

I think 40 and hat

 

[TheUnbiasedOne]

I think 40 and hat

You're right but the hat is 10 roubles

 

[Rokudaime Hokage Naruto]

Bored so I'll explain.

Before the neighbor asks for her money back, the seller has sold the hat and has +10 roubles in his till. These 10 roubles are real because he got them off the neighbor. At this point the neighbor has -25 roubles.

When the seller gives 25 roubles back to the neighbor he now has -15 roubles, the neighbor broke even and the buyer has a free hat along with 15 roubles for free.

Therefore

Neighbor -25 +25 = 0
Buyer +15 + hat
Seller - 15 - hat

Seller is cheated out of 15 roubles and a hat.