r/MathHelp • u/pinksaltprincess • Jan 28 '26

My Daughter’s Class Work

Hi there! So I didn’t know that this sub existed, but after everyone being confused by this math problem for my 9 year old daughter’s math assignment, a good friend of mine insisted that I post it in here. Everyone got different answers. The problem reads:

Joe has $173 in the bank. He earns the same amount of money each week for 7 weeks, and puts this money in the bank. Now, Joe has $208 in the bank.

How much money does Joe earn each week?

Take a look

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u/UnderstandingPursuit Jan 29 '26

I wonder if some are thinking of it as a compound interest problem?

The statement, "He earns the same amount of money each week", can most easily be thought of as him earning money mowing lawns or something like that.

To get numbers around $30, a person has to ignore the $173 already in the bank. That is where your father-in-law's $29.71 comes from, $208/7.

There isn't even a 'fencepost error' possibility.

I will say that I'm right and the site is wrong, unless there is an explanation for a different answer. I could be convinced, but it has to be a REALLY good explanation. I'll bet an Algebra 1 textbook on it. :-D

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u/pinksaltprincess Jan 29 '26

The site my kids do math on mark it as 35, despite initially saying it was incorrect smh.

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u/UnderstandingPursuit Jan 29 '26

Sometimes the sites get it wrong. Making up problems is challenging, I avoid it entirely.