Brain Teaser: Determine the profit this individual makes after selling a cow

A maths brain teaser was shared on Instagram. It has since sparked a debate on the correct answer. The teaser is seemingly simple. It challenges people to decipher the profit an individual earned after buying and selling the same cow twice. Easy, right?
“Let’s test your maths today,” reads the caption to the video shared on Instagram. The question reads, “I bought a cow for $900. I sold it for $1200. I bought it again for $1300. I sold it again for $1600. How much did I earn?”

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The brain teaser was shared two days ago on Instagram. It has since collected over 1.3 lakh likes and the numbers are still increasing. A few puzzle enthusiasts even took to the comments section of the post to share the answers they got after solving the puzzle.
“Why the huge calculation? 900+1300 spent & 1200+1600 earned. 2800-2200=600 profit. Why complications,” posted an individual.
Another added, “He bought at 900 and finally sold it for 1600, so the total profit is 700 but in between he also invested 100 more to buy it again, so finally his investment is 1000 and sold it for 1600, so the total profit is 600.”
“$300. Rest all amount was invested in the purchase of the cow,” commented a third.
A fourth shared, “It’s 300. Because while purchasing a second time, 100 more were invested compared to the previous buy. So it got sold for 1600 in second time, making a benefit of 300.”
“Let’s break it down: 1. Bought the cow for $900 and sold it for $1200, earning $1200 – $900 = $300. 2. Bought the cow again for $1300 and sold it for $1600, earning $1600 – $1300 = $300. So, you earned $300 from each transaction, totalling $600,” wrote a fifth.