# Greek Anthology Book XIV: 7. - Problem/Variant/Mistake

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## Source Work

1992: David Wells: *Curious and Interesting Puzzles*:

- The Puzzles:
- Light Reflected off a Mirror: $20$
- Solution

- Light Reflected off a Mirror: $20$

## Mistake

*$A$ and $B$ together can do a piece of work in $6$ days, $B$ and $C$ together in $20$ days, $C$ and $A$ together in $7 \frac 1 2$ days. How long will each require separately to do the same work?*

The solution is given as:

*$A$, $B$ and $C$ do the whole job in $10$, $15$ and $30$ days respectively.*

## Correction

With the numbers given, the results are actually:

*$A$, $B$ and $C$ do the whole job in $8$, $24$ and $120$ days respectively.*

For the given solution to be correct, it would be necessary for the question to have been:

*$A$ and $B$ together can do a piece of work in $6$ days, $B$ and $C$ together***in $10$ days**, $C$ and $A$ together in $7 \frac 1 2$ days. How long will each require separately to do the same work?

(Emphasis added.)

One of the following things has happened:

- $(1): \quad$ There is an error in the source work, and David Wells has reported it as it has been printed.

- $(2): \quad$ The source work is correct, but a typo has been introduced into the question when it was entered into
*Curious and Interesting Puzzles*.

It has not been possible to check the source work *The Tutorial Arithmetic, 3rd ed.* by W.P. Workman to determine which is the case.

## Sources

- 1992: David Wells:
*Curious and Interesting Puzzles*... (previous) ... (next): Light Reflected off a Mirror: $20$