Riddle Me This?????

[Podunkadunk]

The original poster's question is a lot like the ones you see in the Sunday paper in one of the inserts called "Parade" and the title is "Ask Marilyn". (Marilyn Vos Savant) supposedly has the highest IQ on the planet, or something to that effect. People write in all the time with questions like this...I find them interesting and yes, sometimes I feel so stupid, when in fact I just didn't RTFQ.

Here's my favorite question of all time and her response. Also, read down the thread at all the Ph.D.'s that wrote in that she was wrong in her answer. She gets the last laugh though...

www.marilynvossavant.com :: View topic - Game Show Problem

Podunk

 

[Testman]

Thanks for all replies and formulas that I will never understand. My son is in the 7th grade and the course is algebra 1. He has a real tuff teacher too, there are 32 kids in her class and 26 of them are at 73 or below average, luckily my son has an 89 average.

Thanks again to all your replies.

Also if you see me posting on here again for math answers, it might be my son on here trying to get you to do his homework.

 

[MossRoad]

What state doed the grandfather live in?

The state of confusion, if he reads those formulas!

 

[MossRoad]

Just writer out what the problem states.

Each sibling has a one digit age. Call the ages a and b.

The age of the grandfather is (10*a + b).

Where in the orginal post does it say anything about the granfather's age being 10 times that of the ages of the children added together?

If the children's ages are 7 and 3
then 7 + 3 = 10
It the grandfather's age is 10 time that
then 10 X 10 = 100.


I confused now!!!

 

[riptides]

All I can say,

My kids are coming home with different ways and views on how-to solve things.

Good thing I am open minded, but ya gotta wonder - why mess with things that work.

I fretted over NEW ways to do long division, thank goodness basic algebra and trig aren't changing, for us yet....

It is hard being a kid now-a-days.

-Mike Z.

 

[dooleysm]

Moss:

"The 2 digits in my age are the ages of your brother and sister."

So if the ages of the 2 kids are x and y, then the grandfather's age is either xy or yx (in this case the kids are 7 and 3, so the grandfather's age is either 73 or 37).

Note that another way to write 73 is:
70 + 3

Another way to write 73 is:
7*10 + 3

That's where (10x + y) comes from in the equations I posted.

One of the kids' ages is the ones digit of the grandfather's age, and the other kids' age is the tens digit of the grandfather's age. To turn a single digit (0-9) into a 'tens' digit, we multiply it by 10.

 

[MossRoad]

Moss:

"The 2 digits in my age are the ages of your brother and sister."

So if the ages of the 2 kids are x and y, then the grandfather's age is either xy or yx (in this case the kids are 7 and 3, so the grandfather's age is either 73 or 37).

Note that another way to write 73 is:
70 + 3

Another way to write 73 is:
7*10 + 3

That's where (10x + y) comes from in the equations I posted.

One of the kids' ages is the ones digit of the grandfather's age, and the other kids' age is the tens digit of the grandfather's age. To turn a single digit (0-9) into a 'tens' digit, we multiply it by 10.

I understand all the single digit stuff and solved the riddle back on post three of this thread. What I did not see correctly in your version is that it was

10 times X then adding Y
10x+y
I had read it as 10(x+y)
sorry for the confusion.

 

[dooleysm]

I see, no need to apologize for confusion (at least I hope not, else I owe a BUNCH of apologies).

The Monty Hall problem posted above is very famous. While it's not surprising that so many people get it wrong at first glance, it amazes me that so many PhD's got it wrong. Even if they don't understand the math behind it, I can't believe that they took very many math classes without having heard of the Monty Hall problem. I have a computer science degree (just a plain old BS, no PhD here) and we learned that problem in our very first statistics class. Of course the only ones that got it right were those that had heard it before.

 

[AlanB]

Moss:

"The 2 digits in my age are the ages of your brother and sister."

So if the ages of the 2 kids are x and y, then the grandfather's age is either xy or yx (in this case the kids are 7 and 3, so the grandfather's age is either 73 or 37).

Note that another way to write 73 is:
70 + 3

Another way to write 73 is:
7*10 + 3

That's where (10x + y) comes from in the equations I posted.

One of the kids' ages is the ones digit of the grandfather's age, and the other kids' age is the tens digit of the grandfather's age. To turn a single digit (0-9) into a 'tens' digit, we multiply it by 10.

Thanks, had never seen it that way, but it makes sense.

 

[LMTC]

So if one grandchild was traveling west at 20mph, and the other grandchild left Pittsburgh at 9AM, how old is Grandpa?

Does anyone else recall Pittsburgh being way too frequently used in those traveling car/train questions?