Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 563 reviewsTarget Test Prep

4 digit number

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 232
Joined: Fri Jun 18, 2010 7:09 amFollowed by: 2 members
Thanked: 1 times
by ruplun » Fri Jul 29, 2011 5:10 am
A 4 digit number is chosen at random.What is the probability that all the digits are different?

a. 1/10
b. 1/9
c. 1/4
d. 63/125
e. 73/125
Top
Join the discussion
Source: — Problem Solving |
Newbie | Next Rank: 10 Posts
Posts: 3
Joined: Fri Jul 29, 2011 3:03 am

by tauseef10jan2004 » Fri Jul 29, 2011 6:33 am
(10/10)*(9/10)*(8/10)*(7/10)
=63/125
Top
Join the discussion
User avatar
Master | Next Rank: 500 Posts
Posts: 344
Joined: Mon Sep 14, 2009 5:40 amFollowed by: 3 members
Thanked: 28 times
GMAT Score:700

by sunnyjohn » Fri Jul 29, 2011 6:59 am
Total number of way to choose 4 digits number:

__ __ __ __

> first digit can be any number from 1 - 9. Please note, you can not include 0 because left most 0 digit will make the 3 digits number. For ex- 0123, 0456, 0444 etc.

> Second digit could be anything from 0-9.
> thirst digit could be anything from 0-9.
> fourth digit could be anything from 0-9.

total number of ways : 9 * 10 * 10 * 10

Total number of numbers with all 4 digits different:

> First digit could be anything from 1-9.
> One digit has been chosen, second digit could be anything from 1-9 ( minus 1 digit) or 0.
> 2 digits have been chosen, third digit could be anything from 0-9 ( minus 2 digits)
> 4th digit could be anything from 0-9 ( minus 3 digits).

Total number of way: 9 * 9 * 8 * 7

Now you can find an answer.
Top
Join the discussion