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vinijo
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Using digits 0-9 how many 3 digit no can be formed such tha 21 Jul 2013, 22:34
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67% (01:13) correct 33% (01:13) wrong based on 3 sessions

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Using digits 0-9 how many 3 digit no can be formed such that digits are in descending order?

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Using digits 0-9 how many 3 digit no can be formed such tha 21 Jul 2013, 23:41
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vinijo
Using digits 0-9 how many 3 digit no can be formed such that digits are in descending order?

No OA or answer choices.
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We can select any 3 digits out of 10, and arrange them in descending order. Note that there will be only one descending ordering for each triplet. For, example if we select 0, 3, 7, then the number satisfying the requirement will be 730.

Therefore the answer is simply \(C^3_{10}=120\).

Hope it's clear.
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Using digits 0-9 how many 3 digit no can be formed such tha 18 Jul 2014, 15:19
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Brilliant!! Elegant solution...


Bunuel
vinijo
Using digits 0-9 how many 3 digit no can be formed such that digits are in descending order?

No OA or answer choices.

We can select any 3 digits out of 10, and arrange them in descending order. Note that there will be only one descending ordering for each triplet. For, example if we select 0, 3, 7, then the number satisfying the requirement will be 730.

Therefore the answer is simply \(C^3_{10}=120\).

Hope it's clear.
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Using digits 0-9 how many 3 digit no can be formed such tha 18 Jul 2014, 23:48
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Bunuel
vinijo
Using digits 0-9 how many 3 digit no can be formed such that digits are in descending order?

No OA or answer choices.

We can select any 3 digits out of 10, and arrange them in descending order. Note that there will be only one descending ordering for each triplet. For, example if we select 0, 3, 7, then the number satisfying the requirement will be 730.

Therefore the answer is simply \(C^3_{10}=120\).

Hope it's clear.
Show more


Bunuel isn't this solution a bit too simplistic. For eg say the digits are 6,6 and 6 ( no where mentioned that duplicates not allowed) . In that case no combination will be possible as the numbers are not in descending sequence.Am I looking too much into the problem ?
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Using digits 0-9 how many 3 digit no can be formed such tha 19 Jul 2014, 03:34
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himanshujovi
Bunuel
vinijo
Using digits 0-9 how many 3 digit no can be formed such that digits are in descending order?

No OA or answer choices.

We can select any 3 digits out of 10, and arrange them in descending order. Note that there will be only one descending ordering for each triplet. For, example if we select 0, 3, 7, then the number satisfying the requirement will be 730.

Therefore the answer is simply \(C^3_{10}=120\).

Hope it's clear.


Bunuel isn't this solution a bit too simplistic. For eg say the digits are 6,6 and 6 ( no where mentioned that duplicates not allowed) . In that case no combination will be possible as the numbers are not in descending sequence.Am I looking too much into the problem ?
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Intended meaning of the question is that we are choosing 3 digits out of {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}, no repetitions.
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Using digits 0-9 how many 3 digit no can be formed such tha 19 Jul 2014, 06:59
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The Carson family will purchase three used cars. There are two models of cars available, Model A and Model B, each of which is available in four colors: blue, black, red, and green. How many different combinations of three cars can the Carsons select if all the cars are to be different colors?

A) 24 B)32 C)48 D)60 E)192







Can somebody please provide a lucid explanation?
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Using digits 0-9 how many 3 digit no can be formed such tha 19 Jul 2014, 07:13
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suhaschan
The Carson family will purchase three used cars. There are two models of cars available, Model A and Model B, each of which is available in four colors: blue, black, red, and green. How many different combinations of three cars can the Carsons select if all the cars are to be different colors?

A) 24 B)32 C)48 D)60 E)192







Can somebody please provide a lucid explanation?
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This question is discussed here: the-carson-family-will-purchase-three-used-cars-there-are-128876.html

P.S. Please read carefully and follow: rules-for-posting-please-read-this-before-posting-133935.html

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Using digits 0-9 how many 3 digit no can be formed such tha 20 Jul 2014, 01:26
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Bunuel
vinijo
Using digits 0-9 how many 3 digit no can be formed such that digits are in descending order?

No OA or answer choices.

We can select any 3 digits out of 10, and arrange them in descending order. Note that there will be only one descending ordering for each triplet. For, example if we select 0, 3, 7, then the number satisfying the requirement will be 730.

Therefore the answer is simply \(C^3_{10}=120\).

Hope it's clear.
Show more


I don't know if the following is right. Could you see and evaluate?

3 digits means 3 spaces have to be filled : __ __ __

the first space can contain all digits from (0-9) except 0 and 1. Because, then the requirement of descending order won't be filled. (e.g if first digit is 1, then second digit will be 0 and no option remaining for 3rd digit)

8 * __ * __

the second space can contain all digits except 9,0

8*8*__

the third space can contain all digits except 9,8

8*8*8

= 512
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Using digits 0-9 how many 3 digit no can be formed such tha 20 Jul 2014, 06:05
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hamzakb
Bunuel
vinijo
Using digits 0-9 how many 3 digit no can be formed such that digits are in descending order?

No OA or answer choices.

We can select any 3 digits out of 10, and arrange them in descending order. Note that there will be only one descending ordering for each triplet. For, example if we select 0, 3, 7, then the number satisfying the requirement will be 730.

Therefore the answer is simply \(C^3_{10}=120\).

Hope it's clear.


I don't know if the following is right. Could you see and evaluate?

3 digits means 3 spaces have to be filled : __ __ __

the first space can contain all digits from (0-9) except 0 and 1. Because, then the requirement of descending order won't be filled. (e.g if first digit is 1, then second digit will be 0 and no option remaining for 3rd digit)

8 * __ * __

the second space can contain all digits except 9,0

8*8*__

the third space can contain all digits except 9,8

8*8*8

= 512
Show more

Your answer does not match the correct one (120), so obviously this approach is not right.

The problem with it is that if the first digit is say 2, then the options for the second one is just 2 not 8. So, writing 8*8*8 is wrong.

Archived Topic
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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