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

In the faculty of Reverse-Engineering, 226 second year...

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
Moderator
Posts: 2749
Joined: Sun Oct 29, 2017 2:08 pmFollowed by: 2 members
by AAPL » Wed Mar 21, 2018 7:29 am
In the faculty of Reverse-Engineering, 226 second-year students study numeric methods, 423 second-year students study automatic control of airborne vehicles and 134 second-year students study them both. How many students are there in the faculty if the second-year students are approximately 80% of the total?

A. 515
B. 545
C. 618
D. 644
E. 666

The OA is D.

I solved this PS question of the following way,

NM = 226

AV = 423

Both = 134

Total second year students = (226 - 134) + (423 - 134) + 134 = 226 + 423 - 134 = 515

Assume total students = x

Therefore 0.8x = 515

x = 515/0.8 = 5150/8 = 643 approximately. Option D.

Is there another strategic approach to solve this question? Can any experts help, please? Thanks!
Top
Join the discussion
Source: — Problem Solving |
Legendary Member
Posts: 2604
Joined: Sun Oct 29, 2017 2:04 pmFollowed by: 6 members

by swerve » Wed Mar 21, 2018 9:25 am
Hi AAPL,

You can try as follow,

The total number of students studying both are 423 + 426 - 134 = 515 (subtracting the 134 since they were included in both the other numbers already).

So 80% of the total is 515, so 100% is approximately 644.

Regards!
Top
Join the discussion
Legendary Member
Posts: 2214
Joined: Fri Mar 02, 2018 2:22 pmFollowed by: 5 members

by deloitte247 » Sat Mar 24, 2018 11:49 am
Numeric method = 226 second year students
Automatic control= 423 second year students
Both numeric and automatic = 134 second year students

Therefore, total second year student= (numeric + automatic) - both = [226+423]-134
=649-134= 515 second year students in faculty of reverse engineering. 2nd year student made 80% of the total student.
if 80% =515
then 100%=
$$\frac{\left(515\cdot100\right)}{80}=643.75=644$$
Hence, option D is correct
Top
Join the discussion