Time does fly!
Math brain teasers require computations to solve.
Five years ago, Anthony was three times as old as his sister. Now he is only twice as old. How old are Anthony and his sister?
Answer
Anthony is 20 and his sister is 10. Five years ago he was 15 and she was 5.
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Comments
Sane
Feb 14, 2005
 Five years ago, Anthony was three times as old as his sister. Now he is only twice as old. How old are Anthony and his sister?
let a represent Anthony's age, then s represent the sister
First Statement:
a  5 = (s  5) * 3
a = (s  5) * 3 + 5
Second Statement:
a = s * 2
Combination:
2s = (s  5) * 3 + 5
2s = (s  5) * 3 + 5
2s = 3s  10
s = 10
s = 10
Therefore, Anthony's age is 20 and his sister's is 10. 
Atropus
Feb 15, 2005
 Thanks Sane... I messed up my own figures for how to do that and ended up substituting in instead >. 
Kebron
Dec 06, 2005
 I just thought it through in my head. I have seen one similar to this before. 
sugarnspice4u7
Jan 01, 2006
 hummm... :? 
warmonkey318
Mar 24, 2006
 Ha ha..i guessed and got it right!

yoshinode
Apr 23, 2006
 I m not sure that this 1 would be in the math catergory... i don't no y, but I dont think this is the appropriate catergory for this teaser. 
spazzyjazzy93
Jun 25, 2006
 we did millions of these in my math class this year so i got it right away
nice teaser
yoshinodei guess this could be in the logic category, but i think it belongs in the the category it's in 
flowerz2010
Aug 24, 2006
 That was on my eighth grade mat test, when we were supposed to use variables. So, I got it 
precious1026
Apr 16, 2010
 Everyone seems to have gotten the answer right, so what is the Correction?
I would get only partial credit. Too eager to find the answer. 
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