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vishal_kothari
Group Title
Seven people are in an elevator which stops at ten
floors. In how many ways
can they get o the elevator...
 2 years ago
 2 years ago
vishal_kothari Group Title
Seven people are in an elevator which stops at ten floors. In how many ways can they get o the elevator...
 2 years ago
 2 years ago

This Question is Closed

vishal_kothari Group TitleBest ResponseYou've already chosen the best response.10
get*off*the
 2 years ago

nubeer Group TitleBest ResponseYou've already chosen the best response.0
not sure maybe 10! x 7!
 2 years ago

vishal_kothari Group TitleBest ResponseYou've already chosen the best response.10
no..
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
\( 11^7 \) ?
 2 years ago

vishal_kothari Group TitleBest ResponseYou've already chosen the best response.10
no..
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
what is the answer ?
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
@across: I don't think that's the right answer.
 2 years ago

vishal_kothari Group TitleBest ResponseYou've already chosen the best response.10
(a) 7^10 (b) 10^7
 2 years ago

vishal_kothari Group TitleBest ResponseYou've already chosen the best response.10
answer lies between this two...
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
answer is \( 10^7 \) then.
 2 years ago

AnwarA Group TitleBest ResponseYou've already chosen the best response.0
Oh, I think the answer that across gave assumed that each one gets off in a different floor?
 2 years ago

vishal_kothari Group TitleBest ResponseYou've already chosen the best response.10
how?
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
The problem is modeled as " how many ways can n distinct object can be divided in r distinct groups " some groups may be empty.
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
My earlier answer assumes the superset and I over counted few other cases.
 2 years ago

across Group TitleBest ResponseYou've already chosen the best response.0
FFM is correct.
 2 years ago

vishal_kothari Group TitleBest ResponseYou've already chosen the best response.10
ya..
 2 years ago

across Group TitleBest ResponseYou've already chosen the best response.0
Think of it in smaller terms: suppose there are three floors and two people; they can get off the elevator in 9 different ways, which is \(3^2\) as FFM's model states.\[\]
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
Precisely, my earlier answer assumes that the seven people need not to get off the elevator at all and only some of them get down and all of the other obvious cases.
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
@across: wanna try a variation " atleast one should get off in each floor" ? ; )
 2 years ago

vishal_kothari Group TitleBest ResponseYou've already chosen the best response.10
ok..
 2 years ago

across Group TitleBest ResponseYou've already chosen the best response.0
In this case, though, there are more floors than there are people. :p
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
@vishal kothari: It's a bit hard, don't attempt it if you don't need it.
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
@across: well just increase the numbers :P
 2 years ago

across Group TitleBest ResponseYou've already chosen the best response.0
Let's try 7 floors and 10 people.
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
or more generally any \( r \gt n \)
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
Sorry it should be: or more generally any \( r<n \) pertaining to my above model.
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
@across: Sorry, that doesn't seem correct, as \( n^{ \underline{r} } \) is not the correct assumption, generally people attempt it with mutual inclusionexclusion, but there is a even clever way, If you want I can give you a hint but it would be probably a spoiler.
 2 years ago

pokemon23 Group TitleBest ResponseYou've already chosen the best response.1
anyone willing to explain me about square roots?
 2 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.3
Anyways, always excuse my solecism :P
 2 years ago

robtobey Group TitleBest ResponseYou've already chosen the best response.0
Assume that the elevator riders are considered indistinguishable, for example, 7 warm bodies. There are 11440 ways for them to get off of an elevator servicing 10 floors. http://2000clicks.com/mathhelp/CountingObjectsInBoxes.aspx Refer to: Indistinguishable Objects to Distinguishable Boxes The number of different ways to distribute n indistinguishable balls into k distinguishable boxes is C(n+k1,k1). For those who have access to Mathematica the following is a user defined function called Elevator where r is the number of riders and f is the number of floors. Elevator[ r_ , f_ ] := Binomial[ r + f  1, f  1]
 2 years ago
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