hiijacker-
Make two piles, one with 80 quarters, one with 20.
The pile with 80 quarters will have (t) tails and (80 – t) heads. The pile with 20 quarters will have (20 – t) tails and (t) heads. (0 <= t <= 20)
Flip over every quarter in the pile with 20 quarters and give me $25.
(The pile with 20 quarters will now have (20 – t) heads and (t) tails. (0 <= t <= 20))
Thanks
(Would you like my home address or is Paypal easier?)