Question

if certain number of boys are arranged evenly cyclical form, the 7th boy is directly opposite the 18th boy . How many boys are there?


Please i only need the solution
#thanks

Answer 1

If I give you only the solution, the whole point of this webpage would be futile. I assume you came here to learn and not just to receive answers. So please read this .....

Create a method by setting up a pattern starting with simple cases:

First of all , to have boys directly opposite each other, we must be able to form diagonals, thus we need an even number of boys

place 4 boys evenly spaced around a circle.
so 1 is opposite 3 , 2 is opposite 4
notice that 2(3-1) = 4
2(4-2) = 4

place 6 boys evenly spaced around a circle
so 1 is opposite 4, 2 is opposite 5, 3 is opposite 6
note 2(4-1) = 6
and 2(5-2) = 6
etc

so in our case, ......
tell me what you came up with.

Answer 2

The two boys are separated by 10 others on each side, right?

Now you can easily figure the solution.

Answer 3

thank alot Sir Reiny. Have gotten the right path with you explanation.
sir steve, i also appreciate.

Now i got 22 boys as the answer.