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25!/23!*1/4! =

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Math Expert
Joined: 02 Sep 2009
Posts: 53657

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03 Mar 2019, 23:56
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Difficulty:

15% (low)

Question Stats:

100% (00:25) correct 0% (00:00) wrong based on 18 sessions

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$$\frac{25!}{23!}*\frac{1}{4!} =$$

A. 24
B. 25
C. 48
D. 50
E. 600

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e-GMAT Representative
Joined: 04 Jan 2015
Posts: 2692

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04 Mar 2019, 00:13

Solution

Given:
• An expression $$\frac{25!}{23!} * \frac{1}{4!}$$

To find:
• The value of the given expression

Approach and Working:
We can write 25! as 23! * 24 * 25

• Therefore, $$\frac{25!}{23!}$$ = $$\frac{23! * 24 * 25}{23!}$$ = 24 * 25
• So, the value of the given expression = $$\frac{24 * 25}{4!} = \frac{24 * 25}{24}$$ = 25

Hence, the correct answer is option B.

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Joined: 18 Aug 2017
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Location: India
Concentration: Sustainability, Marketing
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04 Mar 2019, 00:57
Bunuel wrote:
$$\frac{25!}{23!}*\frac{1}{4!} =$$

A. 24
B. 25
C. 48
D. 50
E. 600

solve expression:
$$\frac{25!}{23!}*\frac{1}{4!} =$$
we get
25*24/4! = 25
IMO B
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Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 5357
Location: United States (CA)

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06 Mar 2019, 20:01
Bunuel wrote:
$$\frac{25!}{23!}*\frac{1}{4!} =$$

A. 24
B. 25
C. 48
D. 50
E. 600

We see that 25!/23! = (25 x 24 x 23 x 22 x … x 1) / 23 x 22 x … x 1 = 25 x 24

Continuing with the problem, we have 25 x 24 x 1/4! = 25 x 24 x 1/(4 x 3 x 2) = 25 x 24 x 1/24 = 25

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Scott Woodbury-Stewart

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Re: 25!/23!*1/4! =   [#permalink] 06 Mar 2019, 20:01
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