Chiu Chang Suann Jing/Examples/Example 1
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Example of Problem from Chiu Chang Suann Jing
- Two and a half piculs of rice are bought for $\frac 3 7$ of a tael of silver.
- How many piculs of rice can be bought for $9$ taels?
Answer
Let $x$ be the required quantity.
- $\dfrac x 9$ piculs can be bought with $1$ tael.
Hence $\dfrac x 9 \times \dfrac 3 7$ can be bought for $\dfrac 3 7$ of a tael.
That is:
- $\dfrac x 9 \times \dfrac 3 7 = \dfrac 5 2$
and so:
- $x = 9 \times \dfrac 5 2 / \dfrac 3 7 = 52 \frac 1 2$
$\blacksquare$
One picul, apparently, is equal to about $65$ kilograms.
Sources
- c. 100: Anonymous: Chiu Chang Suann Jing
- 2008: Ian Stewart: Taming the Infinite ... (previous) ... (next): Chapter $3$: Notations and Numbers: Brahmagupta, Mahavira and Bhaskara