Henry Ernest Dudeney/Puzzles and Curious Problems/10 - Mental Arithmetic

Puzzles and Curious Problems by Henry Ernest Dudeney: $10$

Mental Arithmetic

If a tobacconist offers a cigar at $7 \tfrac 3 4 \oldpence$,

but says we can have the box of $100$ for $65 \shillings$,

shall we save much by buying the box?

In other words, what would $100$ at $7 \tfrac 3 4 \oldpence$ cost?

By a little rule that we shall give the calculation takes only a few moments.

Sources

• 1932: Henry Ernest Dudeney: Puzzles and Curious Problems ... (previous) ... (next): Arithmetical and Algebraical Problems: Money Puzzles: $10$. -- Mental Arithmetic