Henry Ernest Dudeney/Puzzles and Curious Problems/150 - Sheep Sharing/Solution

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Puzzles and Curious Problems by Henry Ernest Dudeney: $150$

Sheep Sharing
An Australian farmer dies and leaves his sheep to his three sons.
Alfred is to get $20$ per cent more than John,
and $25$ per cent more than Charles.
John's share is $3600$ sheep.
How many sheep does Charles get?


Solution

Charles gets $3456$ sheep.


Proof

Let $A$, $J$ and $C$ be the number of sheep each of Alfred, John and Charles got respectively.

We have:

\(\text {(1)}: \quad\) \(\ds A\) \(=\) \(\ds J + \dfrac {20 J} {100} = \dfrac {6 J} 5\) Alfred is to get $20$ per cent more than John,
\(\text {(2)}: \quad\) \(\ds A\) \(=\) \(\ds C + \dfrac {25 J} {100} = \dfrac {5 C} 4\) and $25$ per cent more than Charles.
\(\text {(3)}: \quad\) \(\ds J\) \(=\) \(\ds 3600\) John's share is $3600$ sheep.
\(\ds \leadsto \ \ \) \(\ds A\) \(=\) \(\ds \dfrac {6 \times 3600} 5\) substituting from $(3)$ into $(1)$
\(\ds \) \(=\) \(\ds 4320\) substituting from $(3)$ into $(1)$
\(\ds \leadsto \ \ \) \(\ds 4320\) \(=\) \(\ds \dfrac {5 \times C} 4\) substituting into $(2)$
\(\ds \leadsto \ \ \) \(\ds C\) \(=\) \(\ds 3456\) simplifying

$\blacksquare$


Sources