**AMC 10 Mock Exam Question 8**

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?

$\textbf{(A) } 20 \qquad\textbf{(B) } 30\qquad\textbf{(C) } 35\qquad\textbf{(D) } 40\qquad\textbf{(E) } 45$

Submit your answer and solution and explanation below! Solutions will be accepted for 48 hours until 9/9 at 2pm Pacific Time. (There's still time for yesterday's problem too: click here.)

Top solutions for all the Mock Exam questions will be collected and shared as part of a full 25 Question Mock AMC 10 Exam.

Note: The question above is a past AMC problem. Solutions submitted must be written by students. Copied solutions will be disqualified.