BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

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.

★★★★★5.0559 reviews
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
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
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start 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

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

Algebra/Probability

Expert replies
by light_speed » Wed Apr 09, 2008 9:56 am
If an integer n is to be chosen at random from the integers 1 to 96, inclusive, what is the probability that n(n + 1)(n + 2) will be divisible by 8?

A.1/4
B.3/8
C.1/2
D.5/8
E.3/4

I have calculated that there are 57 numbers that are divisible by 8 from the above forumula, but dividing 57/96 to give me an answer is not working. Where am i going wrong?

Thanks!
Join the discussion
Source: — Problem Solving |

by simplyjat » Wed Apr 09, 2008 10:32 am
The answer is definitely not 57. You have to approach these kind of questions differently. You have to identify the pattern. The pattern here is for a multiple of 8 the range 1-8 is similar to 1-96. So you can just concentrate on x between 1-8 and get the desired results.

List down n(n + 1)(n + 2) for all number from 1 to 8
1> 1.2.3 - not divisible by 8
2> 2.3.4 - divisible by 8
3> 3.4.5 - not divisible by 8
4> 4.5.6 - divisible by 8
5> 5.6.7 - not divisible by 8
6> 6.7.8 - divisible by 8
7> 7.8.9 - divisible by 8
8> 8.9.10 - divisible by 8

so we see when x = 2, 4, 6, 7, 8 the sum is divisible is 8. so the answer is 5/8....

Why the answer is same as that of 1-96 is left as an exercise :wink:
simplyjat
Join the discussion

by tomato1 » Wed Apr 09, 2008 10:05 pm
There is a rule that product of two consecutive even no's is multiple of 8.

In this qus n and (n+2) will be consecutive even integers for even values of n. Since there can be 48 even values of n. so n(n+2) will be a multiple
of 8 for 48 values of n.

the product n(n+1)(n+2) can be divisible by 8 in two ways....
1. when product of n(n+2) is multiple of 8. As said above for 48 values of n.


2. when (n+1) is multiple of 8 which is possible when n =7, 15, .........95. that is for 12 values of n.


so n(n+1)(n+2) can be divisible by 8 for 48+12 = 60 values.


thus prob=60/96=5/8
Join the discussion

by humeixia » Thu Apr 10, 2008 2:05 pm
Join the discussion