Henry Ernest Dudeney/Puzzles and Curious Problems/9 - Pocket-Money/Solution

by : $9$

 * Pocket-Money

Solution

 * $3 \shillings 6 \oldpence$

Proof
Tompkins ended up with $1 \oldpence$

Before he paid $3 \oldpence$ to the matchseller, he had $4 \oldpence$

Before spending half of what he had on a bus, he had $8 \oldpence$

Before spending $2 \oldpence$ on a telegram he had $10 \oldpence$

Before spending half of what he had left, he had $20 \oldpence$

Before buying a penny newspaper, he had $21 \oldpence$

Before spending half of what he had on a train ticket, he had $42 \oldpence$

That is, he started with $3 \shillings 6 \oldpence$