The pattern of stones shown is contained completely around the circula

Question

https://gmatclub.com/forum/download/file.php?id=38927 The pattern of stones shown is contained completely around the circular bracelet so that the arc formed by joining the centers of any two adjacent stones is 45°. The number of stones on the bracelets is (A) 5 (B) 6 (C) 8 (D) 10 (E) 12 2017-11-30_0949_002.png

niks18 · Answer

Each arc equals  45°

Number of stones = number of arcs

So number of arcs =  \frac{360°}{45°}=8

Option  C

arvind910619 · Answer

A very valuable point to note here is that when there are stones arranged in a straight line there would be n-1 segments .
But when they are connected in circle there would be as many segments as stones .

Shobhit7 · Answer

In my opinion, it's best to imagine the entire ring and manually count the stones, just to avoid any calculation error.

There are 8 stones on the ring.

Ans C

Posted from my mobile device

niks18 · Answer

Hi @Shobhit

Can you explain How one can imagine and manually calculate the number of stones without knowing the angle between them or without knowing that the stones are equally spaced?

If the angel between the stones would have been 10 then there would have been 36 stones are if the stones were not equally spaced then the number could have been different.

I think you need to know the number of sectors first and the may be visualise the ring with all sectors and stones on it

Sent from my iPhone using  GMAT Club Forum mobile app

Shobhit7 · Answer

Hi,

What I meant was, considering the data in the given figure, we know that there are 8 equally spaced sectors of 45 degrees each. Basis, we can imagine the ring and manually count the stones as well. This is just to avoid double counting any stone that's part of two adjacent sectors.

Posted from my mobile device

brs1cob · Answer

C is the correct answer.

360/45 = 8

gatz · Answer

360/45=8
Answer (C) 8

AlphaCentauri4ly · Answer

The pattern of stones shown is contained completely around the circular bracelet so that the arc formed by joining the centers of any two adjacent stones is 45°. The number of stones on the bracelets is

(A) 5
(B) 6
(C) 8
(D) 10
(E) 12

Show Spoiler

Attachment:

2017-11-30_0949_002.png

(A) 5 
(B) 6 
(C) 8
(D) 10 
(E) 12

A circle has 360 degrees.

If two adjacent stones make 45 degrees then 360/45 make 8 stones.

stne · Answer

Dear Moderator,

What Am I missing here, if each 45 degrees contains 2 stones , then when there are 8 - forty five degrees , shouldn't we do 8*2 = 16 stones .
Hope you can help, thank you.

warrior1991 · Answer

Visualize here. When you take consecutive stone, suppose starting with 1 and 2 , the angle makes 45 degree. Now when you move further you will take 2 and 3 to make a 45 degree. So you see 2 is counted twice. In all each stone will be counted only once and not twice. Hence we will not multiply. Hope that helps!! If yes, Do not forget to give Kudos !!

The pattern of stones shown is contained completely around the circula

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The pattern of stones shown is contained completely around the circula

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