Please check

Expert replies

saurabhmahajan: Master | Next Rank: 500 Posts; Posts: 250; Joined: Thu Jan 07, 2010 2:21 am; Thanked: 10 times

by saurabhmahajan » Sun Oct 17, 2010 10:34 pm

Hi Friends,

I am currently working on permutation and combination chapter. yesterday i was at the ATM and just thought how many combinations of my pin can be done IF no zero (0) should be there in my pin. I did the following way. Please check and let me know if i was right.

four numbers in pin which are repeatable.
so for first number 9 choices (1-9)
for second also 9 choices
for third also 9 choices
for fourth also 9 choices

so total combinations would be 9*9*9*9 = 6561
am i correct ?

Thanks and regards,
Saurabh Mahajan

I can understand you not winning,but i will not forgive you for not trying.

Like this post

Source: Beat The GMAT — Problem Solving | Sun Oct 17, 2010 10:34 pm

GMAT/MBA Expert

Ian Stewart: GMAT Instructor; Posts: 2623; Joined: Mon Jun 02, 2008 3:17 amFollowed by: 355 members; Location: Montreal; Thanked: 1090 times; GMAT Score:780

by Ian Stewart » Sun Oct 17, 2010 11:03 pm

Yes, you are correct!

For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

ianstewartgmat.com

Like this post

diebeatsthegmat: Legendary Member; Posts: 1119; Joined: Fri May 07, 2010 8:50 amFollowed by: 3 members; Thanked: 29 times

by diebeatsthegmat » Mon Oct 18, 2010 2:19 am

saurabhmahajan wrote:Hi Friends,

I am currently working on permutation and combination chapter. yesterday i was at the ATM and just thought how many combinations of my pin can be done IF no zero (0) should be there in my pin. I did the following way. Please check and let me know if i was right.

four numbers in pin which are repeatable.
so for first number 9 choices (1-9)
for second also 9 choices
for third also 9 choices
for fourth also 9 choices

so total combinations would be 9*9*9*9 = 6561
am i correct ?

wow... study everywhere....

nice

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

563 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (563 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