Brain Teasers
Circle of Children
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?
Hint
How many children are in half of the circle?Answer
22; in half of the circle there are 11 children because 18-7=11. Multiply 11x2=22!Hide Hint Show Hint Hide Answer Show Answer
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Comments
As usual I got this math teaser the long way. I've got to bone up on my algebra!
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.
Bit EZ but i enjoyed it. Thanks.
riddle is right. There is nothing to do with Algebra. I'm glad everyone seems to like it
We do these as bonus questions in school all the time!
my brain hurts
i got 20 but i'm not entirely sure how
i got 20 but i'm not entirely sure how
I needed the hint.
but ast least then I got it!
good one!
but ast least then I got it!
good one!
good 1 even tho i dont understand y u need to subtract 7 from 18 to get 11 to multiplay it by two?
Simple, but good.
Good teaser!
good 1
Thanx!!!
Fun!
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.
Then I realized I could have just doubled 10 and added 2.
Sigh I'm ashamed of my stupidity.
The solution assumes that the children are arranged consecutively around the circle.
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.
So 18 - 7 = 11. 2 * 11 = 22.
Good teaser BTW.
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