Henry Ernest Dudeney/Puzzles and Curious Problems/133 - Sawing and Splitting/Solution

by : $133$

 * Sawing and Splitting

Solution

 * $3 \tfrac 1 {13}$ cords

Proof
Let $n$ be the number of cords they are to work on.

We have that:
 * $\dfrac n 5 + \dfrac n 8 = 1$

from which we get:
 * $8 n + 5 n = 40$

That is:
 * $n = \dfrac {40} {13} = 3 \tfrac 1 {13}$