Sun Tzu Suan Ching/Examples/Example 3

Example of Problem from Sun Tzu Suan Ching

There are $3$ sisters, of whom the eldest comes home once every $5$ days,

the middle every $4$ days,

and the youngest in every $3$ days.

In how many days will all the $3$ meet together?

Solution

$60$ days.

Proof

The answer is found by:

$\map \lcm {4, 5, 3}$

$\blacksquare$

Sources

• c. 280 -- 473: Sun Tzu: Sun Tzu Suan Ching
• 1913: Yoshio Mikami: The Development of Mathematics in China and Japan
• 1992: David Wells: Curious and Interesting Puzzles ... (previous) ... (next): Sun Tsu Suan Ching: $71$