Red and Blue Marbles (Solution)

I’d put one red marble in one urn, and the rest of the marbles in the other urn. The probability you pick a red marble is

\[P = 0.5 * (1) + 0.5 * (49 / 99) \\ P \approx 0.75\]

Almost, but not quite, 75%, so I’d pay almost $75.