Henry Ernest Dudeney/Modern Puzzles/4 - Loose Cash

by : $4$

 * Loose Cash


 * What is the largest sum of money -- all in current silver coins and no four-shilling piece -- that I could have in my pocket without being able to give change for half a sovereign?

Solution
The largest sum possible is $15 \mathrm s. 9 \mathrm d.$, composed of:
 * one crown and one half-crown (or $3$ half-crowns)
 * $4$ florins
 * one threepenny piece.

Proof
Recall the list of silver coins in the time of :


 * The threepenny piece: $3$ (old) pence
 * The sixpence: $6$ (old) pence
 * The shilling: $12$ (old) pence
 * The florin: $24$ (old) pence
 * The half-crown: $30$ (old) pence
 * The crown: $60$ (old) pence
 * The half sovereign: $120$ (old) pence.

's mention of the four-shilling piece refers to a coin in circulation for a short time in the late $19$th century, also known as the double florin.