ELI5. This math problem

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I saw this on discord and I feel like an idiot but I’m so confused.

*”Question for you guys If I borrow $50 from my mom and $50 from my dad to purchase an object worth $97. Since I would have $3 change I would give one to my mom and one to my dad and keep one my self
So I still owe my mom $49 and my dad $49 that means I owe $98 counting the one I have makes is $99 where did the other $1 go?”*

In: Mathematics

12 Answers

Anonymous 0 Comments

You owe $98 total. And you have $98 worth of stuff ($97 object plus $1). 98 including the one you have is just 98, not 99.

Anonymous 0 Comments

“Counting the one i have” doesn’t make any sense for the problem. It doesn’t make sense to count the $1 he has as something he/she owes their parents. And the $100 value is also completely irrelevant so the “other dollar” doesn’t matter

In short, this is nonsense 🙂

Anonymous 0 Comments

It’s a misdirection. You do owe $98 total, having paid $2 back. That third dollar you kept, you down’t owe yourself.

Anonymous 0 Comments

The dollar didn’t “go” anywhere. The next to last Line incorrectly says you “have” 99 dollars. You don’t have 99 dollars, you have 1 dollar. You owe 98 dollars still.

Consider thst if you split the 3rd dollar into 50 cents, then you would only owe 97 and it would be equal across parents.

Anonymous 0 Comments

IIRC, the logic error is that you’re changing from tracking the money to tracking what you owe and then mixing up the different terms into one calculation, which aren’t the same thing. I don’t recall the technical jargon.

I do remember how to solve it: count the *dollars alone* from the end backward. Mom has a dollar, Dad has a dollar, I have a dollar. The other $97 are at the store.

Anonymous 0 Comments

Everything in that sentence is logically correct until “counting the one I have makes is $99”. Why would you add the amount you owe with the amount you have? If I have 1,000 and I owe you 500, does the sum of 1500 have any significance at all?

Anonymous 0 Comments

It is poorly written. Okay here we go.

The problem says that Dude borrows a total of $100 to purchase a $97 item. What he then has are two $50 debts. He spends $97, leaving him with $3. He puts $1 towards each debt, leaving him with two $49 debts and a dollar which he is keeping.

What he actually has is a $97 dollar item, a dollar in hand, and two $49 dollar debts. The way the problem is written leads you to assume that all those things should add up to one hundred, like this:

49+49+1=100

That is of course incorrect. What it should look like is kind of a before and after on each side of the equation. His loans on one side and the purchase price and change on the other. Like so:

$50+$50=$97+$3

The change then being distributed to his parents and himself.

Anonymous 0 Comments

You owe $98, and you have $1.

You can’t add what you have to what you owe without keeping track of the sign.

Debts are usually expressed as negative, so you HAVE -$98 and you HAVE $1, so if you wanted to add that up, the total would be -98 + 1 = -97. Debt of 97 and object worth 97.

Anonymous 0 Comments

I don’t understand. What exactly is “the problem”?
To me it looks like you’re just adding together random numbers and then wondering why they’re not equal to $100.
The $98 dollars you owe includes the $97 you paid, and the $1 in your hand. So why are you adding the $98 you owe and the $1 you have together? The former includes the latter.

Anonymous 0 Comments

This problem is only difficult because it’s worded like a spider web. Anyways, let’s map this out:

You have $3 in change. After giving $1 back to each of your parents, you’ve returned $2 total. The money you owe is equal to the price minus the amount you’ve already returned, so $100-$2=$98. The $1 is useless for finding out how much you owe, since it’s not the price or the money you’ve returned, so it’s just a word play.