another dilemma:you've got three doors (num1, num2 and num3) and only one brings u a ferrari (or whatever)you chose one door for ex, num2.after your first choice, I tell u that the ferrari is not behind num1now, you can change your choice or not,what do you do?

You switch. Do you work for HR?

why?hr: no!

See link for the Steinmetz solid

If it's not behind #1 and you've chosen #2, you have 50% of winning whether it's behind #2 or #3 (whether you switch or not). Seems to be too easy may be you meant another question.sure of your proba?think about it.....

Not Monty Hall AGAIN !!! this comes up every few weeks on the Brainteaser forum.

boratu is right ... the answer is 16/3 thanks to my friend Google

boratcan u explain how you get the bounds for your integral? There is a nice coloured picture on one of the links above but how do you get from that to setting up the axes?

gut feeling for 2 is that the intersection is a sphere of radius 1 , so its 4/3 pi

Yeah, great book for analytical geomaetryQuoteOriginally posted by: zooeyQ2 : I think its not just the area of the cylinder for the intersection. I think we should do an integral for this...may be a double integral over the region.. ask me after couple of days and I can tell u the ansswer as I am currently refreshing the calculus tht I leanrt in college ...but u shud find the method in Adv. Calc. and Analytical Geo. by Thoman and Finney

I remember seeing that integral in further A-level maths but just used common sense....volume of a cylinder......but, int is the actual way!

it is not a sphere ... why dont u do a search on google for "intersecting cylinders" ?

Silverside, on my diagram, one cylinder has axis along the z axis, the other along the x axis. By symmetry the intersection of the two cylindrical surfaces (in the positive x-y-z octant) is a curve joining the point (0, 1, 0) and the point (1, 0, 1). This curve projects onto the line z=x on the z-x plane. You then integrate over a triangular area on the z-x plane from this line to the line z =1 (where the cylinder cuts this plane) and multiply by 8 x 2.

DreamonSTreet:Just curious to know that which company asked you the second question in interview and how much time was given to respond. It seems to involve multiple integral from analytical geometry.ThanksQuoteOriginally posted by: dreamonstreet1. You and I play a game. I have 0.6 probability to win the game. Now I want to double my stake to 2 dollars, if you agree, we'll play, if you don't, then you give me 1 dollar. Will you agree or not? What if mywinning probability is 0.8?2. Suppose that 2 cylinders each with radius 1 intersect at right angles and their centers also intersect. What is the volume of the intersection??thanks

QuoteOriginally posted by: silversideNot Monty Hall AGAIN !!! this comes up every few weeks on the Brainteaser forum.The fact that you should switch seemed counterintuitive to me for 3 doors, but it's easier to understand it for let's say 5 doors: if you picked one and somebody opens other 3 for you, and there's no prize there, of course you should switch to the one (out of 4 doors) you haven't picked initially