Bunuel wrote:
Trickster Rabbit agrees with Foolish Fox to double Fox's money every time Fox crosses the bridge by Rabbit's house, as long as Fox pays 40 coins in toll to Rabbit after each crossing. The payment is made after the doubling, Fox is excited about his good fortune until he discovers that all his money is gone after crossing the bridge three times. How many coins did Fox have at the beginning?
(A) 20
(B) 30
(C) 35
(D) 40
(E) 45
Let's
test the answer choices.
We know that the answer can't be A (20), because the game would be over after Fox crosses the bridge ONCE.
So, let's start with B (30)
Fox starts with 30 coins1st bridge crossing: double coins to have 60 coins. Pay 40 coins. 20 coins remaining.
2nd bridge crossing: double coins to have 40 coins. Pay 40 coins. 0 coins remaining.
GAME OVER.
Fox is supposed to cross THREE times.
Eliminate B
Test C (35)
Fox starts with 35 coins1st bridge crossing: double coins to have 70 coins. Pay 40 coins. 30 coins remaining.
2nd bridge crossing: double coins to have 60 coins. Pay 40 coins. 20 coins remaining.
3rd bridge crossing: double coins to have 40 coins. Pay 40 coins. 0 coins remaining.
PERFECT! Fox crossed exactly THREE times.
Answer: C
Cheers,
Brent
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