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Probability-Ice cream

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Probability-Ice cream

by sulabh » Sat Jun 28, 2008 9:58 pm
There are only three varities of ice creams in Jokaland priced at Rs 5,Rs 10 and Rs 15.If, Arun buys 4 ice creams for Rs 45 from Jokaland, then what is the probability that any two of them together will cost exactly Rs 20 ?

A.1/2
B.1/4
C.3/4
D.3/8
E.5/12

Answer and my explanation after discussion.
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by TrizMA » Sun Jun 29, 2008 2:55 pm
is answer E: 5/12?

Only two comibination of 4 ice cream for Rs.45 are possible

i) 5,10,15,15
ii) 10,10,10,15


i)5,10,15,15
total 6 combination possible. two combinations give 20

ii) 10,10,10,15
total 6 combination possible. three combinations give 20


Total desired combinations=5
Total combinations=12

prob=5/12

pls tell if it's correct
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by sulabh » Mon Jun 30, 2008 12:55 am
Yup thats right.
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by TrizMA » Mon Jun 30, 2008 1:02 am
sulabh, u wrote:

i)5,10,15,15
total 6 combination possible. 3 combinations give 20

pls show three combinations which give 20.

i can only count 2 combinations. 1)5,15 2)5,15.

what's the third combination which gives 20?

If OA 1/2, then there must be some other approach to this. What's the OA?
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by TrizMA » Mon Jun 30, 2008 1:05 am
sorry sulabh, my bad. a blopper :oops:
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Re: Probability-Ice cream

by beeparoo » Wed Jul 02, 2008 8:35 am
sulabh wrote:There are only three varities of ice creams in Jokaland priced at Rs 5,Rs 10 and Rs 15.If, Arun buys 4 ice creams for Rs 45 from Jokaland, then what is the probability that any two of them together will cost exactly Rs 20 ?

A.1/2
B.1/4
C.3/4
D.3/8
E.5/12

Answer and my explanation after discussion.
Did you make up this question, sulabh? If so, I have some questions for you.
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