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

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

Again from my practice test

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Data Sufficiency |
Master | Next Rank: 500 Posts
Posts: 258
Joined: Mon Aug 27, 2007 12:43 pm
Thanked: 15 times

by ri2007 » Sun Sep 09, 2007 9:19 am
I would say the answer is D, r =2

I got this by plugging in possible values of t in the equation.

Pls confirm if the answer is correct.

Also if any one can suggest a better way than plugging in values would appreficate it

thanks a lot
Last edited by ri2007 on Sun Sep 09, 2007 10:51 am, edited 1 time in total.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 460
Joined: Sun Mar 25, 2007 7:42 am
Thanked: 27 times

by samirpandeyit62 » Sun Sep 09, 2007 10:19 am
Q says t^2 + 5t + 6 is divided by 7 with remainder r

stmt 1: when t is divided by 7, the remainder is 6

so we can say let t-6 (t -reminder) = x (where x will be divisible by 7)

so t =x + 6

putting this in eqn we have (x + 6) ^ 2 + 5(x+6) + 6 / 7
i.e (x^2 +17x + 72) / 7
i.e x^2/7 + 17x/7 + 72/7

now here the first two fractions will yield an integer value (no remainder as x is divisile by 7)

so 72/7 will produce the remainder

so the remainder is 2 SUFF

stmt 2: t ^ 2 / 7 gives 1 as remainder

working with t^2 will produce a root in the above eqn
so we have

let t - a (remainder of t/7) = x

so t = x+ a
i.e t^2 = (x +a) ^2
i.e. x^2 + a^2 + 2ax
divide this by 7
so we have x ^2/ 7 will be an integer
2ax /7 wll be an int

so remainder is produced by a^2/7 and this should be 1

so possible values of "a" can be 1-6 if you check with these
u will get 1/7 will give remainder 1
& 6^2 / 7 will give remaider 1

so a can be 1 or 6

so we can say that we t is divided by 7 it will give remainder 1 or 6
so t^2 will give remainder as 1

you can check this with 8 & 13
now as we calculated for stmt 1 t/7 with remainder 6, same value is here so we can say that if a =6 then remainder for eqn is 2

now for a=1
we can say
t-1 =x
so t=x +1

put in eqn provided
i.e (x +1 )^2 +5(x+1) +6/7

solving we get

x^2/7 + 7x/7 +12/7

now here again first two fractions will yield a integer value only remaider will be added coz of 12/7 which will be 5

so we have two remainders here henec INSUFF

so ans must be A
Regards
Samir
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 27
Joined: Tue Sep 04, 2007 2:29 pm

TT

by TT » Mon Sep 10, 2007 6:59 am
You are right again. The answer is A. Thanks again.

TT
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 321
Joined: Tue Aug 28, 2007 5:42 am
Thanked: 1 times

by kajcha » Mon Sep 10, 2007 7:00 am
Ans should be A

I agree with Samir's explanantion of stmt 1.

For stmt 2 - I solved like this (I think this is faster)

t^2-1 = 7n => t^2 = 7n+1 => t = sqrt(7n+1)

Fitting this into equation given in Q we get
(t^2+6)/7 will have remainder 0. t^2 gives remainder 1. 6+1 = 7

now, we need to find what is the remainder of [5*sqrt(7n+1)]/7.. putting values which are easy to calulcate

Say, n = 5 gives 30/7 remainder 2
Say, n = 9 gives 40/7 remainder 5

So, stmt 2 is NOT SUFF
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 460
Joined: Sun Mar 25, 2007 7:42 am
Thanked: 27 times

by samirpandeyit62 » Mon Sep 10, 2007 7:49 am
Yes Kajcha,
Your approach would be little faster, I did not use it because I thought it would be better of to work without the square root sign (mentioned it in my post).
Regards
Samir
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 321
Joined: Tue Aug 28, 2007 5:42 am
Thanked: 1 times

by kajcha » Mon Sep 10, 2007 9:19 am
After thinking over it again, I realised we really don't have to use sqrt at all... this approach will be even faster

t^2 + 6 will give remainder 0

We just need to calculate for 5*t/7 ... substitue values

t = 6 remainder is 2
t = 8 remainder is 5

PS: I chose 6 and 8 to satisfy stmt 2 .
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 460
Joined: Sun Mar 25, 2007 7:42 am
Thanked: 27 times

by samirpandeyit62 » Mon Sep 10, 2007 9:30 am
Kajcha,
If anyone gets this kind of a problem on the GMAT he/she will definitely remember u while solving it. Thanks for these shortcuts.
Regards
Samir
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1