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
Vote for Target Test Prep, Newsweek Readers’ Choice Awards 2026
NEWSWEEK READERS’ CHOICE 2026

BIG NEWS! Target Test Prep has been nominated, and they’d love your vote!

TTP has worked incredibly hard to build the best test prep experience possible, and winning Newsweek’s 2026 Readers’ Choice Award for Best Test Prep would mean a lot to them. If TTP has helped you, they’d be incredibly grateful for your vote. You can vote once each day through September 9.

Vote for TTP
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
Start free 5-day trial
Read 559 reviewsTarget Test Prep

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

Trial of a new drug

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 17
Joined: Sat Oct 03, 2009 2:41 pm
by adamz » Thu Nov 24, 2011 5:03 pm
In a trial of a new drug, patients received a progressively growing dosage of the drug for a few days. On the first day, each patient received 15 milligrams of Drug. On each of the following days, the daily dosage was k milligrams greater than the dosage received the day before, reaching a dosage of 43 milligram on the last day of the trial. For how many days did the trial last, if each patient received a total amount of 145 milligrams of drug during the whole trial ?

(a) 4
(b) 5
(c) 6
(d) 7
(e) 9

OA:B
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
User avatar
Legendary Member
Posts: 1101
Joined: Fri Jan 28, 2011 7:26 amFollowed by: 13 members
Thanked: 47 times
GMAT Score:640

by HSPA » Thu Nov 24, 2011 6:43 pm
Arth Series:

A = 15, d= k; An = 43; n/2 * (2A+ (n-1)d) = 145.. All these are sufficent to find n.
First take: 640 (50M, 27V) - RC needs 300% improvement
Second take: coming soon..
Regards,
HSPA.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Master | Next Rank: 500 Posts
Posts: 102
Joined: Thu Jul 21, 2011 2:22 amFollowed by: 1 member
Location: Lahore, Pakistan
Thanked: 4 times

by chufus » Thu Nov 24, 2011 8:01 pm
There is definitely something wrong with the question.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 176
Joined: Thu Sep 22, 2011 5:32 am
Thanked: 5 times

by vishal.pathak » Thu Nov 24, 2011 8:58 pm
adamz wrote:In a trial of a new drug, patients received a progressively growing dosage of the drug for a few days. On the first day, each patient received 15 milligrams of Drug. On each of the following days, the daily dosage was k milligrams greater than the dosage received the day before, reaching a dosage of 43 milligram on the last day of the trial. For how many days did the trial last, if each patient received a total amount of 145 milligrams of drug during the whole trial ?

(a) 4
(b) 5
(c) 6
(d) 7
(e) 9

OA:B
Assume that the no of days = n

Day 1: 15
Day 2: 15 + k
Day n: 15 + (n-1)k

15 + (n-1)k = 43 .......... (1)
If we sum all these terms, we will have 15n, k*(The sum of an AP). The AP will be (1 + 2 + .. + (n-1))

so
15n + k(n-1)(2 + (n-2))/2 = 145 ........... (2)(I have used the formula for the sum of an AP)

Putting the value of (n-1)k from eqn (1) in eqn(2), we get,

15n + 14n = 145
so n = 5. Therefore, answer is B
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Master | Next Rank: 500 Posts
Posts: 102
Joined: Thu Jul 21, 2011 2:22 amFollowed by: 1 member
Location: Lahore, Pakistan
Thanked: 4 times

by chufus » Fri Nov 25, 2011 1:30 am
Yup B is correct. Sorry for my earlier post.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Community Manager
Posts: 1060
Joined: Fri May 13, 2011 6:46 amFollowed by: 52 members
Location: Utrecht, The Netherlands
Thanked: 318 times

by neelgandham » Fri Nov 25, 2011 2:30 am
From the question, The amount(in milligrams) of daily dosage of the drug is in AP.

(number of terms/2)*(First Term + Last Term) = Sum of the Terms
(number of days/2)*(First Dosage + Last Dosage) = Total amount
(number of days/2)*(15+43) = 145
(number of days)*(15+43)/2 = 145
(number of days)*29 = 145
(number of days = 5)

Answer : B
Anil Gandham
Welcome to BEATtheGMAT | Photography | Getting Started | BTG Community rules | MBA Watch
Check out GMAT Prep Now's online course at https://www.gmatprepnow.com/
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 1255
Joined: Fri Nov 07, 2008 2:08 pmFollowed by: 90 members
Location: St. Louis
Thanked: 312 times

by Tani » Fri Nov 25, 2011 7:32 am
Try backsolving this one.
The dosage grew from 15 to 43 units, therefore the incremental dose on the last day was 28 units.
This means the total number of days in the study minus one (allowing the start day) has to be a factor of 28. Looking at our answer choices, only B works.
Tani Wolff
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 88
Joined: Sat Oct 15, 2011 6:38 pmFollowed by: 1 member
Thanked: 1 times

by gmatpup » Fri Nov 25, 2011 7:51 am
Tani Wolff - Kaplan wrote:Try backsolving this one.
The dosage grew from 15 to 43 units, therefore the incremental dose on the last day was 28 units.
This means the total number of days in the study minus one (allowing the start day) has to be a factor of 28. Looking at our answer choices, only B works.

I did this exact thing!

I got the answer B by doing the following:

Since 43-15 = 28, again, we have to look for a factor of 28. I used 7.

Thus:

15 (add 7), 22 (add 7), 29 (add 7), 36 (add 7), 43 (add 7)

Add this up and we do end up getting the 145

So now we can see that it took 5 days :)

I hope this helps!
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 1255
Joined: Fri Nov 07, 2008 2:08 pmFollowed by: 90 members
Location: St. Louis
Thanked: 312 times

by Tani » Fri Nov 25, 2011 8:00 am
Good work!

My most difficult teaching task is often convincing my strongest math students to use backsolving and picking numbers. Even if you can solve tough problems using sophisticated math, you can often save time and gain confidence by using simple strategies. Also, when faced with a tricky problem you will have more tools at your disposal.
Tani Wolff
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1