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Mathematician Over To You? - Education (7) - Nairaland

Nairaland ForumNairaland GeneralEducationMathematician Over To You? (27856 Views)

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Re: Mathematician Over To You? by blackslayer: 3:28pm On Aug 17, 2025
You just need to go through this thread, then you will see why Nigeria is a failed state!
Re: Mathematician Over To You? by udeh3(m): 3:37pm On Aug 17, 2025
He made just $10 and that's from the last sales
Re: Mathematician Over To You? by blackslayer: 3:40pm On Aug 17, 2025
This puzzle isn’t really testing math skills, it’s testing reading discipline.

If you skim, your brain tends to “auto-complete” and assume the question means total profit.

But the wording “Then, he buys it back at $80 but sells it again for $90. How much did he make?” — grammatically — points to the last transaction only.
Re: Mathematician Over To You? by Ezechimma(m): 3:43pm On Aug 17, 2025
He made $20
Re: Mathematician Over To You? by Kalulu44: 3:44pm On Aug 17, 2025
The total money he invested in the two purchases is $70 and he sold for $90. Definitely he made $20 profit!
Re: Mathematician Over To You? by Kalulu44: 3:46pm On Aug 17, 2025
udeh3:
He made just $10 and that's from the last sales
In the total transaction, how much did he invest? You said last sales as if it didn't start from the first sale
Re: Mathematician Over To You? by Rex777: 3:48pm On Aug 17, 2025
AI is good, the answer is $20
Re: Mathematician Over To You? by JustAndy(m): 4:00pm On Aug 17, 2025
From the accounting aspect of this post bro, the man has not made any profit because after making $10 from the previous sales, he had to add extra $10 to the $70 to buy back at a higher cost of $80 dollar and sell at $90, so he only got back the $10 dollar he added as extra cost to rebuy... No profit
Re: Mathematician Over To You? by Euromillion200: 4:06pm On Aug 17, 2025
Made losses if you factor in the cost of logistics and time.
Re: Mathematician Over To You? by ikofficial: 4:09pm On Aug 17, 2025
Common sense no common at for those saying $10and $20 profit
He made non profit Zero returns
Just come sense calculations
Re: Mathematician Over To You? by Ushernwamama(m): 4:12pm On Aug 17, 2025
A man buy Goat $60
Resale it $70
$70-$60 = ($10)

Then the same rebougbt the same Goat $80
His initial profit $10 (now he takes $10 from his savings making it total $70 he used to buy the goat from his own pocket)

* Remember his $10 gain entered and his additional $10 equally entered

Now he sold it finally at $90
$90 - $70 = $20

I used to say $10 but as I calm down do the mathematics I noticed his total expenditures is $70 his gain is $20

Initial $10 plus additional $10
Re: Mathematician Over To You? by TheBizGenius: 4:16pm On Aug 17, 2025
kingyang:
Alright, let's break down the problem step by step to understand how much profit the man made from these transactions involving the goat.

### Understanding the Problem

We have a sequence of buying and selling actions:

1. **First Purchase:** Buy a goat for \$60.
2. **First Sale:** Sell the goat for \$70.
3. **Second Purchase:** Buy the goat again for \$80.
4. **Second Sale:** Sell the goat again for \$90.

Our goal is to calculate the total profit made from these transactions.

### Calculating Profit Step by Step

**Profit** in such transactions is calculated by considering the money spent (costs) and the money earned (revenue). The total profit is the total revenue minus the total cost.

Let's list out the inflows (money received) and outflows (money spent):

1. **First Purchase:**
- Action: Buy goat
- Amount: \$60 (outflow)

2. **First Sale:**
- Action: Sell goat
- Amount: \$70 (inflow)

3. **Second Purchase:**
- Action: Buy goat again
- Amount: \$80 (outflow)

4. **Second Sale:**
- Action: Sell goat again
- Amount: \$90 (inflow)

Now, let's sum up the inflows and outflows separately.

**Total Outflows (Money Spent):**
- First purchase: \$60
- Second purchase: \$80
- **Total spent:** \$60 + \$80 = \$140

**Total Inflows (Money Earned):**
- First sale: \$70
- Second sale: \$90
- **Total earned:** \$70 + \$90 = \$160

**Total Profit:**
- Profit = Total earned - Total spent
- Profit = \$160 - \$140 = \$20

### Verifying with Individual Transactions

Sometimes, it's helpful to look at the profit from each buy-sell pair to ensure our answer makes sense.

1. **First Buy-Sell Cycle:**
- Bought for \$60, sold for \$70.
- Profit: \$70 - \$60 = \$10

2. **Second Buy-Sell Cycle:**
- Bought for \$80, sold for \$90.
- Profit: \$90 - \$80 = \$10

**Total Profit:**
- \$10 (first cycle) + \$10 (second cycle) = \$20

This matches our previous calculation, confirming that the total profit is indeed \$20.

### Potential Missteps

It's easy to get confused when the same item is bought and sold multiple times. One might mistakenly think to subtract the selling prices from the buying prices in sequence without considering that each sale is independent of the previous purchase after the first sale.

For example, someone might think:

- First sale: \$70 - \$60 = \$10 profit.
- Then buys again for \$80: thinks they're now at a loss because \$80 is more than \$70, but this isn't correct because the first transaction is already closed with a \$10 profit.
- Then sells for \$90: \$90 - \$80 = \$10 profit.
- Total: \$10 + \$10 = \$20.

This approach also leads to the correct answer, but it's crucial to recognize that each buy-sell pair is independent in terms of calculating profit.

### Alternative Approach: Net Cash Flow

Another way to look at it is to track the net cash flow at each step, starting from \$0.

1. **Start:** \$0
2. **Buy for \$60:** -\$60
3. **Sell for \$70:** -\$60 + \$70 = +\$10
4. **Buy for \$80:** +\$10 - \$80 = -\$70
5. **Sell for \$90:** -\$70 + \$90 = +\$20

At the end, the net is +\$20, which is the total profit.

### Conclusion

After carefully analyzing the transactions through multiple methods—summing total inflows and outflows, calculating profit per buy-sell cycle, and tracking net cash flow—we consistently arrive at the same conclusion.

**Final Answer:** The man made a total profit of **\$20**.
I read and read your analysis and I laughed. You are very correct.

But I feel all you needed to have explained should have been;

1. I raise N60, I go buy goat wey I sell for N70

2. I raise another N80, I go buy another goat wey I sell for N90.

But I applaud your analysis because you said something very profound; see it as 2 different transactions. It totally blew my mind. That is the ultimate Ibo container shop sense.

That's why Ibo traders always say "No matter the price, we no dey ever lose because na just to make small profit on top amount wey we buy".

Once again, I bow to your analytical ability. People like you no plenty again. Trust me on that
Re: Mathematician Over To You? by jimoholuyemi3(m): 4:19pm On Aug 17, 2025
Let's break down the transactions step by step:

Buys goat for $60
Money spent: -$60

Sells goat for $70
Money received: +$70
Net after first transaction: $70 - $60 = +$10

Buys goat back for $80
Money spent: -$80
Net after buying back: $10 - $80 = -$70

Sells goat again for $90
Money received: +$90
Net after last transaction: $90 - $70 = +$20

Total profit made = $10 (from first transaction) + $10 (from second transaction) = $20

Answer:
The man made $20 in total.
Re: Mathematician Over To You? by member13(m): 4:32pm On Aug 17, 2025
Ayokequeen:
Many of you shouting "he made$20 profit" are not fit for business at all because the likes of you usually take the gross as your overall profit while forgetting to remove some contingencies and be left with the net.

He started the business with $60 and made $10 profit in the first transaction making $70 altogether but he bought the same item back at $80 (a loss of $10) and then sold it back at $90 (a profit of $10 cancelling the first loss)

The guy made no profit.
The problem did not say he started the business with $60. It simply said he bought a goat for $60. No one knows how much he initially had. Why would you assume he spent all his initial capital on buying the goat? I have a business and I have never, ever spent all my capital on buying anything.
Re: Mathematician Over To You? by member13(m): 4:36pm On Aug 17, 2025
maisauki:
In the first transaction, he made 10 bucks,very correct
BUT
When he wanted to buy it again, he had to source for 10 bucks to add to the 70 in his hands to make 80 for the new buying price
Why assume that he didn’t also source the initial $60? Why is everyone assuming he only had $60 to begin with. The problem simply says that he bought a goat for $60. It didn’t say that a man with a capital of only $60 bought a goat for $60.
Re: Mathematician Over To You? by 3kay945(m): 4:39pm On Aug 17, 2025
I have looked at it very well.

He made $20.

End of discussion.

I don't want to hear any arguments again.

For those not understanding,...

Try this.. use borrow capital to explain to yourself cheesy
Re: Mathematician Over To You? by Neonzone: 4:47pm On Aug 17, 2025
The total profit made was Zero . If you follow the transactions carefully, he made nothing. All the transactions were +A+(-A)=0.
Re: Mathematician Over To You? by PDPdestroyer(m): 4:51pm On Aug 17, 2025
muyico:
Simple equation but logic! Who can solved this equation??
The wordings of the text clearly says…”he then buys it back….” meaning he bought the same goat back at a price $10 higher than he sold it. Selling it at a price $10 higher than the cost means he made no profit
Re: Mathematician Over To You? by Alexdegreat(m): 4:55pm On Aug 17, 2025
muyico:
Simple equation but logic! Who can solved this equation??
0$
Re: Mathematician Over To You? by Sirkingsnado: 4:56pm On Aug 17, 2025
muyico:
Simple equation but logic! Who can solved this equation??
Let me use my self as an example

I took 60 from my mother box to buy goat and the end of the day I sold it 70


When going home I will keep my 60 to her box and keep 10 in my pocket


Let the next day I took 80 from my mother box and buy same goat at the end of the day I sold it 90


When going home I will keep 80 in my mother box

And keep 10 for my self


Total gain 20
Re: Mathematician Over To You? by ADAMUdaCOWBOY: 5:03pm On Aug 17, 2025
Stainlezzking:
the two people above me, saying $10 is funny. he made $20 in total.
You have a sharp kidney. don't mind them
Re: Mathematician Over To You? by ADAMUdaCOWBOY: 5:05pm On Aug 17, 2025
Jashub:
Sorry to say but you definitely did not comprehend the question
No he did. You did not. When he bought the goat for #
$60 and sold it for $70, he made $10 profit. Keep the profit aside. He got $80 from god alone knows where and bought a goat and sold it for $90 making another $10 profit. Altogether he made $20 profit. Gerrit?
Re: Mathematician Over To You? by ADAMUdaCOWBOY: 5:06pm On Aug 17, 2025
Sirkingsnado:
Let me use my self as an example

I took 60 from my mother box to buy goat and the end of the day I sold it 70


When going home I will keep my 60 to her box and keep 10 in my pocket


Let the next day I took 80 from my mother box and buy same goat at the end of the day I sold it 90


When going home I will keep 80 in my mother box

And keep 10 for my self


Total gain 20
Your kidney is indeed working
Re: Mathematician Over To You? by ADAMUdaCOWBOY: 5:08pm On Aug 17, 2025
PDPdestroyer:
The wordings of the text clearly says…”he then buys it back….” meaning he bought the same goat back at a price $10 higher than he sold it. Selling it at a price $10 higher than the cost means he made no profit
The first deal was done and dusted with a profit of ten dollars. The second deal was successful too with a profit of $10. Altogether, $20 profit in the bag.
Re: Mathematician Over To You? by Jashub: 5:08pm On Aug 17, 2025
ADAMUdaCOWBOY:
No he did. You did not. When he bought the goat for #
$60 and sold it for $70, he made $10 profit. Keep the profit aside. He got $80 from god alone knows where and bought a goat and sold it for $90 making another $10 profit. Altogether he made $20 profit. Gerrit?
...this is why many of you fail at math and business . When he sold the goat and made a profit of $10, did he not add an extra 10 rebuy the goat ? How then did he make a total of $20 ? ...Or are you not seeing the math ? Chai...undecided
Re: Mathematician Over To You? by ADAMUdaCOWBOY: 5:10pm On Aug 17, 2025
Ayokequeen:
Many of you shouting "he made$20 profit" are not fit for business at all because the likes of you usually take the gross as your overall profit while forgetting to remove some contingencies and be left with the net.

He started the business with $60 and made $10 profit in the first transaction making $70 altogether but he bought the same item back at $80 (a loss of $10) and then sold it back at $90 (a profit of $10 cancelling the first loss)

The guy made no profit.
Hanty, which kain business woman you be? he bought goat and you say he lost? Each of those two transactions are independent business transactions, don't mix them up.
Re: Mathematician Over To You? by Josephkabila12: 5:11pm On Aug 17, 2025
$20
Re: Mathematician Over To You? by DeepSight(m): 5:13pm On Aug 17, 2025
This question has absolutely nothing to do with math or raher kindergarten arithmetic.
Re: Mathematician Over To You? by immaculatesense(m): 5:15pm On Aug 17, 2025
PDPdestroyer:
The wordings of the text clearly says…”he then buys it back….” meaning he bought the same goat back at a price $10 higher than he sold it. Selling it at a price $10 higher than the cost means he made no profit
After u read all the comments you still came up with wrong answer? Na una Dem go write answer for board una go still miss am.
May AI will help you.
Person chop $10 each from both transactions which makes it $20 in all you still dey give contrary answer.
Oya
I buy car for $100,000 and sell am to you $150,000. I come buy am from you $200,000 and sell am back for your $250,000.

Shey na me lose abi na you. Oya talk make I may whether you get small sense abi nothing dey upstairs.
Re: Mathematician Over To You? by Juliearth(f): 5:15pm On Aug 17, 2025
PuZZyNegro:
Following your calculations, he made $10 when he sold for $70.

Now, he went to buy back the same product but this time, he added the $10 profit to the $60 initial capital and borrowed $10 to purchase the item, leaving him with no initial gain anymore but $10 debt.

The he sold the product for $90. He will first remove the $10 borrowed, leaving him with $80. The total profit will now be $20. The reason is because, if he set out with $60 and is returning with $80, he's had additional $20 irrespective of how many transactions were performed to achieve that.
Both transactions are completely independent. The capital and profit from the first business should not be considered as capital for the second transaction. Math- based questions should not be treated as Economics
Re: Mathematician Over To You? by Fcwilly: 5:19pm On Aug 17, 2025
(sell + see) - ( buy + buy)
(70+90 =160) - ( 60+80=140 )
160-140=$20
Re: Mathematician Over To You? by ellizy(m): 5:22pm On Aug 17, 2025
He made $20 profit...
This is just simple logic our mothers use in their daily trade without the knowledge of dy dx..
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