#1
Dartboard: Assuming that a dart will always hit the board what is the probability of hitting the yellow disk, if the inner circle has a radius of 3 the middle circle has a radius of 4 and the outer circle has a radius of 7?



Could someone please solve this?
#3
1/2

EDIT: 3/10, I think actually.

EDIT 2: It's actually 3/7 >_<
Last edited by michal23 at Jul 13, 2009,
#4
Quote by Amndisleanda

Could someone please solve this?


why?
Hahahahahahahahahah hahahaha har har har
#6
Damn it, I read the title as "Meth Problem".
Basses:
Fender Precision Bass
Fender Jazz Bass
1967 Fender Coronado Bass II
Warwick Star Bass
Squier Precision Bass TB
#7
Which one is yellow??
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#8
That picture doesn't work.

I can picture no yellow circles on a dart board.

I agree, I don't think it's half. Depends where the damn "yellow circle" is.
#9
Work out the area of the whole board and then take away the red and blue areas.

And then something yeah I haven't done maths in like a year and a half.
#10
This would be really easy, if you actually explained it properly.
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#12
if i tell you the answer, will you sex me up?

i think its 33/49.
Hahahahahahahahahah hahahaha har har har
#13
**** it, where's my calculator?


EDIT: 2/3 chance it will hit the yellow.
Last edited by Acdc1991 at Jul 13, 2009,
#14
Blue - 3
Red - 4
Yellow - 7

3 + 4 + 7 = 14 - the yellow 7 = 7

7/14
1/2

am I missing something here?


I havent done maths in a good 4 years, so I'm probably wrong


EDIT: Wait, what's the question?

bah, **** it
Last edited by sam b at Jul 13, 2009,
#15
I'll stab a guess at it.

Its not 1/2, as the area of a circle is pi multiplied by the radius squared. However, you need to take away the area of the inner circles to get the area of yellow, That means the blue circle has an area of 9 pi, the red of 7 pi and the yellow of 33pi. The total area of the circle is justthose three added, which is itself just pi multiplied by the yellow circles radius squared.

it would make more sense if i knew how to use math formulae symbols on the pc. Il let you calculate the probability yourself, ive got a fish supper to eat!
X


"Just wait till tomorrow
I guess that's what they all say
Just before they fall apart"
#16
^^ Yeah you're adding up radius instead of area. I used pi x radius squared.
#17
It's 3/7, I'm pretty certain. Think about it, if the inner circle has a radius of 3, and the middle circle has a radius of 4, because the inner circle is INSIDE the middle circle, together they still have a radius of 4. Similarly, the outercircle has a radius of 7, but because of the two other circles INSIDE it, the yellow band is only 3 out of that 7. Thus 3/7.
#18
surface of yellow / total surface

The surface of a circle is pi * r^2, but Pi can be left out of the equation here, so the surface is r^2

49-16 / 49 = 33/49

/thread

EDIT: McTodd had it before me.
#19
Quote by basilbrush
McTodd had it before me.

what do i win?
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#20
FFS. Right I worked out the area of the dartboard(49 x pi) this came to 153.9.

Then I worked out the area of the blue and red (16 x pi) = 50.265.

Subtract to get the area of the yellow ring = 103.6725575

So the area of the blue and red is 50.625, area of the yellow is 103.6725575.

The yellow takes up 2/3 of the board (or 67%).
#21
Quote by sam b
Blue - 3
Red - 4
Yellow - 7

3 + 4 + 7 = 14 - the yellow 7 = 7

7/14
1/2

am I missing something here?


I havent done maths in a good 4 years, so I'm probably wrong


EDIT: Wait, what's the question?

bah, **** it


Put it like this.

Inner circle is i

Middle circle is m

Outer circle is o

Yellow circle is y

We know that ir=3, mr=4, or=7. As o is the outer circle we have to assume it's the full "scoring" board.

Problem is, we don't know what the hell y is.
#22
Quote by basilbrush
surface of yellow / total surface

The surface of a circle is pi * r^2, but Pi can be left out of the equation here, so the surface is r^2

49-16 / 49 = 33/49

/thread

EDIT: McTodd had it before me.


Yeah this is the right answer, I done it the long way. There's a 67% chance that it will hit the yellow.
#23
Quote by Acdc1991
Yeah this is the right answer, I done it the long way. There's a 67% chance that it will hit the yellow.


What IS the yellow? WHERE is the yellow?