Circle of Children
Math brain teasers require computations to solve.
A number of children are standing in a circle. They are evenly spaced and the 7th child is directly opposite the 18th child. How many children are there altogether?
HintHow many children are in half of the circle?
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Answer
22; in half of the circle there are 11 children because 187=11. Multiply 11x2=22!
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Comments
onlyeeyore
Jun 15, 2005
 As usual I got this math teaser the long way. I've got to bone up on my algebra! 
Riddlerman
Jun 15, 2005
 Algebra ain't anything to do with it. Just figure 10 kids either side of them (10) Double it as there are two sides (20), then add the two kids themselves (22)
Bit EZ but i enjoyed it. Thanks. 
sk8ergrl
Jun 15, 2005
 riddle is right. There is nothing to do with Algebra. I'm glad everyone seems to like it 
BrUnEttEcUtiE
Jun 15, 2005
 We do these as bonus questions in school all the time! 
sweetime
Jun 15, 2005
 my brain hurts
i got 20 but i'm not entirely sure how 
tamjp
Jun 16, 2005
 I needed the hint.
but ast least then I got it!
good one! 
PCDguitar
Jun 17, 2005
 good 1 even tho i dont understand y u need to subtract 7 from 18 to get 11 to multiplay it by two? 
Question_Mark
Jun 17, 2005
 Simple, but good. 
froggygg
Jun 22, 2005
 Good teaser! 
amanduh05
Jun 23, 2005
 good 1 
sk8ergrl
Mar 20, 2006
 Thanx!!! 
tintiniscool
Aug 06, 2006
 Fun! 
opqpop
Sep 11, 2010
 I'm such an idiot. I figured out there were 10 kids on the right, and then figured out there were 6 kids before the 7th kid on the left, and hence 4 kids after the 18th kid to the left, for a total of 18 + 4 = 22 kids.
Then I realized I could have just doubled 10 and added 2.
Sigh I'm ashamed of my stupidity. 
doctapeppaman
Sep 27, 2012
 The solution assumes that the children are arranged consecutively around the circle. 
Jimbo
Jun 03, 2013
 The question may be considered by solving a simpler problem. If 4 kids stand in a circle, 1 is opposite 3 and 2 is opposite 4. The difference in position is always 2. Double it to find the number.
So 18  7 = 11. 2 * 11 = 22. 
Jimbo
Jun 03, 2013
 Good teaser BTW. 
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