Brain teaser/ math expert help needed!!!!

[Spookwriter]

Try to convert it to months. 91 x12 = 1,092 months.

Divide by 3...one guy was twice as old, showing three units.

1,092 divided by 3 gives me 364 months.

364 divided by 12 months gives me 30.33333

30.3333333 times 2 units = 60 years 6 months (the older man)

30.3333333 would be as 30 years 3 months

That adds up as 90 years, 9 months.

I need three more months...2 to the older man, 1 to the young man.

So my final guess is...

Old man....60 years, eight months......60x12+8= 728 months
Younger....30 years, four months........30x12+4= 364 months

728 months plus 364 months equal 1,092 months.

Am I right?

 

[Ms.FuzzyButts]

Quote:
Stop throwing rocks at my house and read the question again!! It isn't as simple as it looks.

 

[SunnyCalifornia]

I don't have a graphing calculator anymore, but here's how'd you do it..

graph the function y=91-x


Then graph the function y=1/2x.....edit: Wait, I think this equation might be wrong... let me think a bit more

Where the two lines intersect is your answer!

 

[FireTigeris]

Quote:
wait, lets see- but there Smith was never twice Jone's age...

53 & 38
52 & 37
51 & 36
50 & 35
49 & 34
...
38 & 15 <---- where smith is the same age you say Jones is now...

 

[Cindiloohoo]

In order to have a combined age of 91 the older man had to have an even number age, which was double the odd number age of the younger man at some point. 13 and 26 works, 15 and 30 , 17 and 34, etc. So what is said is the older man at some point was twice the age of the younger, but now is not. My answer works for 23 years ago. If Smith is now 53 and Jones is now 38.

23 years ago they were 15 & 30.

 

[FireTigeris]

Quote:
But you can't pick a random time for Smith to be twice as old as Jones, it must be at the same point that Jones is currently = Smith age.

Given that Jone's current age is X
When Smith age = twice jones age, smith's age = x

 

[chickendude]

Holly mackerel I'm lost. I have to go for now. But I will check back later. Thanks to all who are helping and continue to put in their 2 cents.

 

[Sugar Sand Farm]

I cheated but heres the answer
The combined age of two people is 91. Person A is twice as old as person
B was when Person A was as old as Person B is now. How old is each person?

>>...The combined age of two people is 91...<<

Translation into algebra: A + B = 91

>>...Person A is twice as old as person B was when Person A was as old as
Person B is now...<<

Do a little bit of rewording in terms of "X years ago", and make
these two new sentences from it:

>>...Person A is twice as old as person B was X years ago...<<
>>...X years ago was when Person A was as old as Person B is now...<<

Taking the first new sentence:
>>...Person A is twice as old as person B was X years ago...<<

X years ago, B wsa B-X, so

A = 2(B-X)

Taking the second :

>>...X years ago Person A was as old as Person B is now...<<

X years ago, A was A-X. So

A-X = B

So we have three equations and 3 unknowns:

A + B = 91
A = 2(B-X)
A-X = B

Can you solve that system of equations? If not post again.

Answer: A = 52, B = 39, X = 13

Checking:

Their combined age is 91. 52+39 = 91. That checks
>>...Person A is twice as old as person B was X years ago...<<
13 years ago B was 39-13 or 26, and A is 52 which is twice that.
That checks.
>>...X years ago Person A was as old as Person B is now...<<
13 years ago Person A was 52-13 or 39, and that's how old Person B
is now, so that checks.

Edwin
AnlytcPhil@

 

[FireTigeris]

Quote:
But you can't pick a random time for Smith to be twice as old as Jones, it must be at the same point that Jones is currently = Smith age.

Given that Jone's current age is X
When Smith age = twice jones age, smith's age = x

I said that kinda odd:

Hummm-

It's like this:

When I was ten I was twice as old as my brother, he is now ten - how old am I?

 

[geosheets]

smith 52
jones 39