Permutaiton and Combination -Letter Problem

Expert replies

s91arvindh: Junior | Next Rank: 30 Posts; Posts: 22; Joined: Sat Apr 19, 2014 5:24 am

by s91arvindh » Sat May 03, 2014 2:29 am

4 letters are randomly selected from PROPORTION.

a) Number of ways for selecting 3 alike and one different
b) Number of ways for selecting 2 alike and 2 others alike
c) Number of ways for selecting 2 alike and 2 other different
d) Number of ways for selecting all 4 different

Requesting to help me on solving this question.

P.S Answers are not available since I got the questions from a Handout

Like this post

Source: Beat The GMAT — Problem Solving | Sat May 03, 2014 2:29 am

Quasar Chunawala: Newbie | Next Rank: 10 Posts; Posts: 7; Joined: Wed Apr 16, 2014 9:41 pm; Thanked: 4 times

by Quasar Chunawala » Sat May 03, 2014 3:57 am

Given data
The frequency of each of the distinct alphabets in the word PROPORTION are:
P = 2, R = 2, O = 3, T = 1, I = 1, N = 1
Total no. of alphabets with repetitions = 10
Total no. of distinct alphabets = 6

a) No. of ways to select 3 alike = 1
No. of ways to select 1 different from 5 distinct letters = C(5,1) = 5
Total no. of ways = 5 x 1 = 5

b) No. of ways to select 2 alike = 3
Remaining letters are 2.
No. of ways to select the other 2 alike = 2.
Total no. of ways = 3 x 2 = 6

c) No. of ways to select 2 alike = 3
Remaining letters are two.
No. of ways you can select 2 distinct letters from 5
= C(5,2) = 10
Total no. of ways = 3 x 10 = 30

d)No. of ways of selecting all 4 different.
C(6,4) = C(6,2) = 21.

Experts, need your help on this one!

Like this post

GMAT/MBA Expert

Brent@GMATPrepNow: GMAT Instructor; Posts: 16207; Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members; Location: Vancouver, BC; Thanked: 5254 times; GMAT Score:770

by Brent@GMATPrepNow » Sat May 03, 2014 6:04 am

s91arvindh wrote:4 letters are randomly selected from PROPORTION.

a) Number of ways for selecting 3 alike and one different
b) Number of ways for selecting 2 alike and 2 others alike
c) Number of ways for selecting 2 alike and 2 other different
d) Number of ways for selecting all 4 different

Requesting to help me on solving this question.

P.S Answers are not available since I got the questions from a Handout

Please post only one question per thread. Otherwise things can become pretty complicated when there are discussions on multiple questions.

Cheers,
Brent

Brent Hanneson - Creator of GMATPrepNow.com

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

559 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review