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HongHu
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A has to deliver dinner to three rooms. B has to deliver 27 Jan 2005, 23:27
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A has to deliver dinner to three rooms. B has to deliver flowers to the same three rooms. They can't go to the same room at the same time. How many possible ways can they do it?



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A has to deliver dinner to three rooms. B has to deliver 28 Jan 2005, 01:38
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I am getting 36. If it is correct, I can explain.
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lovely_baby
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A has to deliver dinner to three rooms. B has to deliver 28 Jan 2005, 04:42
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the answer is 3C1x2C1x3!=36
Lets assume
d1, d2, d3 dinners in each rooms
f1, f2, f3 flowers...
pairs with the same index (d1, f1), etc. cannot occur
then
A can deliver dinner in 3C1 rooms
B can deliver flowers in in 2C1 rooms
add that the order of delivering is important should multiple by 3!
(because of three rooms)
then getting the answer
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twixt
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A has to deliver dinner to three rooms. B has to deliver 28 Jan 2005, 06:17
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Hong Hu could you please post the OA or provide us with your point of vue. I just tried to figure out some examples and I still get 18...
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banerjeea_98
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A has to deliver dinner to three rooms. B has to deliver 28 Jan 2005, 09:21
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37 ways ?

I think it is 36+1...as the stem doesn't say that A and B should be working at the same time, so there is one more way when they A OR B (order doesn't matter) deliver their stuff first to all rooms and then the other one delivers to all rooms.
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A has to deliver dinner to three rooms. B has to deliver 28 Jan 2005, 11:19
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There are 9 total ways to do it.
In 3 ways they will be together in the same room

So possible ways=9-3=6.

Plz post the OA.
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HongHu
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A has to deliver dinner to three rooms. B has to deliver 28 Jan 2005, 15:33
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lovely_baby
the answer is 3C1x2C1x3!=36
Lets assume
d1, d2, d3 dinners in each rooms
f1, f2, f3 flowers...
pairs with the same index (d1, f1), etc. cannot occur
then
A can deliver dinner in 3C1 rooms
B can deliver flowers in in 2C1 rooms
add that the order of delivering is important should multiple by 3!
(because of three rooms)
then getting the answer
Show more


Lovely_baby's got the right answer, and she explained it perfectly. I translated this from Chinese, so I would have to apologize if the question is not clear enough. :)
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banerjeea_98
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A has to deliver dinner to three rooms. B has to deliver 28 Jan 2005, 16:17
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HongHu
lovely_baby
the answer is 3C1x2C1x3!=36
Lets assume
d1, d2, d3 dinners in each rooms
f1, f2, f3 flowers...
pairs with the same index (d1, f1), etc. cannot occur
then
A can deliver dinner in 3C1 rooms
B can deliver flowers in in 2C1 rooms
add that the order of delivering is important should multiple by 3!
(because of three rooms)
then getting the answer

Lovely_baby's got the right answer, and she explained it perfectly. I translated this from Chinese, so I would have to apologize if the question is not clear enough. :)
Show more


I agree with it till 36 combinations, however, as I said before, I think we need to add 1 more way to this combination. As the ques doesn't state that each of them have to be working at the sametime, there is a possibilty that A OR B will finish his/her job first and then he next one will......any takers of this extra way ? :)
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HongHu
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A has to deliver dinner to three rooms. B has to deliver 28 Jan 2005, 16:31
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Yes, this is where I didn't translate the question correctly. It did say that there are three time slot, and both A and B needs to do their chores in these time slots. :)
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banerjeea_98
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A has to deliver dinner to three rooms. B has to deliver 28 Jan 2005, 17:44
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HongHu
Yes, this is where I didn't translate the question correctly. It did say that there are three time slot, and both A and B needs to do their chores in these time slots. :)
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good, then I take that 1 extra way out of my ans of 37, agree with 36 now.
keep these ques coming



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Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Problem Solving (PS) Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
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