A PHP Error was encountered

Severity: Warning

Message: Missing argument 2 for FAQ::showDoubt()

Filename: controllers/faq.php

Line Number: 153

A PHP Error was encountered

Severity: Notice

Message: Undefined variable: seotitle

Filename: controllers/faq.php

Line Number: 157

For Career Guidance: TopCoaching.com  |   (011)4562-9345, (011)4570-1751  |  GMAT  |  GRE  |  Log In Here  |  Create Free Account
Top Coaching  
Home ›FAQ

Doubt & Answer Explanation

Doubt

How many different numbers, which are smaller than 2 x 10^8 and can be written by means of the digits 1 and 2?
1)

766

2)

765

3)

764

4)

763

5)

None of these
sir, the ques was for 2 * 10^8 and ans is given as 1...so i needed the explanation



Answer Explanation

For numbers smaller than 2 x 10^8:

For the number with 1 digit, number of combinations = 2^1
For the number with 2 digit, number of combinations = 2^2

similarly,
For the number with 8 digit, number of combinations = 2^8

For the number with 9 digit, all the numbers can start only with 1 ( for number to be less than 2*10^8), hence number of combinations = 1*2^8

 
Total numbers that can be formed are = 2^1+2^2+2^3+2^4+2^5+2^6+2^7+2^8+2^8 =766


hence option (1)

A PHP Error was encountered

Severity: Notice

Message: Use of undefined constant MBA_DISCOUNT_LAST_DATE - assumed 'MBA_DISCOUNT_LAST_DATE'

Filename: include/adserver.inc

Line Number: 645

CAT coachingMBA 2011 Entrance Exams Full Length Mock Tests Series

  • 40 full length online mock CAT exams based on official CAT pattern & interface released by IIM
  • 6 Full Length FMS Tests
  • 6 Full Length IIFT Tests
  • 6 Full Length JMET Tests
  • 5 Full Length XAT
  • 3 Full Length MHCET Tests
  • 3 Full Length ICET Tests
  • 3 Full Length NMAT Tests
  • 2 Full Length SNAP Tests
  • 5 Full Length MAT
  • Ask unlimited number of doubts to topCATcoaching faculty
  • Personalized recommendations based on your performance
  • Receive SMS alerts for all important MBA exam events
  • Compare your performance against the nation
Rs 1000/- less 35% discount = Final Price Rs 600/-
Buy Now
For questions call: (011)4562-9345, (011)4570-1751

Home | Company Overview | topCATcoaching.com Faculty | Doubts Answered by Faculty | Management Team | Contact us | Our Facebook Page
IIT & AIEEE  |  AIPMT, AIIMS & AFMC  |  CA-CPT  |  BBA, BBS & BBE  |  CLAT  |  CAT  |  Bank PO  |  GRE  |  GMAT  |  Career Guidance

© 2011 Prism Education Private Limited. All rights Reserved.