Can you guys help with this math problem of the week

[tripletots]

This is an optional problem for my son to do and he hasn't even looked at it yet because it's not due until Friday. However, I really enjoy doing them, but this one has me stumped and it's driving me crazy. Can you guys help me figure it out?

Maxie lies on Fridays, Saturdays, and Sundays, but he is truthful on all other days. Minnie lies on Tuesdays, Wednesdays, and Thursdays, but she is truthful on all other days. On what day of the week could they both say, "Tomorrow I will lie?"

By the way, I won't tell my son. It's optional and for fun.

 

[pooh6890]

Good one! Wish I had an answer for you though...

 

[DrCavin]

Thursday - Maxie is telling the truth on Thursday & says she will lie on friday - Minnie lies on thursday & says she will lie on friday....

 

[nanabear]

They can both say it on Thursday. Max lies on Friday so he is being truthful. Minnie doesn't lie on Fridays, but she can say she will on Thursday because that is a day she can lie (she can say it, but she'll be lying).

 

[Debbru]

I think Thursday. When Maxie says "tomorrow I will lie" he is telling the truth and will lie on Friday. On Thursday when Minnie says "tomorrow I will lie" she is lying, since she tells the truth on Friday.

 

[Cindy B]

I would set it up as a chart.

Make a name header and the days of the week as columns...

And for one row you will have one of the persons name and either a Y or a N (for yes or no lying) on each day of the week.

Repeat for the other name.

I guess after you fill in the chart with your Y's and N's, you will find two of the same.

 

[Debbru]

Wow - I can't believe you got that many replies in the time it took me to type my post!

 

[Diva of Dragons]

On what day of the week could they both say, "Tomorrow I will lie"?

Hmmmm, I wonder if this is a trick question. The problem does not state whether or not this (above) would be a true statement when they said it.

The best answer I have is Thursday.

For Maxie, it would be true, because he/she lies on Fridays.
For Minnie, it would be a lie, because she lies on Thursdays.

But, that is one day they could/would both say it, according to the given parameters.

ETA: Some people type way faster than me!! LOL!!

 

[DrCavin]

Do I have to take the final since I answered first??

 

[JR6ooo4]

thursday is my answer also, but I stopped at one answer since I am at work...

Mikeeee

 

[ProudMomTo3Boys]

Before I read all of the other responses I also got Thursday.

 

[MM27]

I agree it's Thursday. Maxie says "tomorrow I will lie" and is telling the truth because Friday is a lie day. When Minnie says it she is on a lie day so telling you she is going to lie means that she will tell the truth.

 

[tripletots]

Wow, you guys are not only good but you're quick. I totally see it now, and it was driving me crazy.

Now I will report back by Thursday and let you know if my DS 10 got it right. He's much smarter in math than I am. His brain just works math problems differently than the rest in our family. So I'm curious to see if he can get this one.

Thanks again.

 

[nephthys43]

yup... thursday

 

[agnes!]

Thursday.

On Thursday if Minnie says "Tomorrow I will lie" she is lying because tomorrow(Friday) she will tell the truth, but that's ok because she's *lying* about it.
If Maxie says on Thursday "Tomorrow I will lie" she is telling the truth because Friday is one of her days to lie.

agnes!

 

[bookgirl]

Thursday.

Maxie would be telling a truth on Thursday that he will lie on Friday and Minnie will be telling a lie on Thursday because that is a day she lies on even though she will be honest on Friday.

Answered before I read the other answers.

 

[DVC_Princess]

Hi... sorry my post is so late... i was just reading this now. I also got Thursday, but thought I would mention my reasoning behind it.

If he's learning positive and negative numbers (or if not, then it's an opportunity to introduce it), you can call truth (+) and lying (-). So if you're looking for the day when they are lying it's (+)(-)=(-). [If you were looking for the day when they were telling the truth, it's (+)(+)=(+) or (-)(-)=(+).]

Then set up 2 columns and 2 rows (columns are + and - for days telling the truth and days lying), rows are for each person. Add the days of the week (M, T, W, Th, etc) into each of the 4 boxes based on the problem. Then look for the day (Thursday) when you can pick the following day (Friday) and have it be in the opposite column for each person.

Does that make sense? Hope it helps

 

[AtlantaSue]

I was just about to ask, "how is this a math problem?"-but I guess DVC answered for me!

 

[tripletots]

I was just about to ask, "how is this a math problem?"-but I guess DVC answered for me!

I was wondering the same thing, thanks DVC, you explained it perfectly.

OP here, my son did the problem while I was gone (I took my 3 DD's to get their ears pierced) and when I got back he had his answer of Thursday. I couldn't believe it, he got it. He made a chart just like you guys said but I didn't tell him to do it., he just did it. I didn't think he'd do it until tomorrow since it's not due until Friday.


Anyway, thanks for all the correct answers.

 

[KSchwagg86]

Well, my head almost exploded reading that so I was just going to say everyday--but I guess the answer is Thursday!