This “cow puzzle” is really just a multi-step profit-tracking problem disguised as something tricky.
You do two separate buy-and-sell cycles:
First cycle:
Buy for $800, sell for $1,000 → profit = $200
Second cycle:
Buy for $1,100, sell for $1,300 → profit = $200
Now add both profits:
$200 + $200 = $400 total profit
A quick way to double-check is total cash flow:
- Total spent: $800 + $1,100 = $1,900
- Total received: $1,000 + $1,300 = $2,300
Net profit: $2,300 − $1,900 = $400
The confusion usually comes from focusing on the higher repurchase price ($1,100), but each buy-sell pair is its own completed transaction. Once you separate them correctly, the result is straightforward.
