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
GMATBootcamp Starts Sep 21
Chris Peckover, Target Test Prep GMAT expert
LIVE ONLINE BOOTCAMP

Live Online Bootcamp Class with Top GMAT Expert Chris Peckover

Sep 21 to Oct 9, 2026

Schedule
Mon to Fri · 7:00 to 10:00 PM ET
Included
Live classes + 6 months of TTP OnDemand
  • Boost your GMAT score in less than one month in a live online class
  • 6 months access to TTP OnDemand video courses included
View bootcamp & 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.

Sets - Any shortcuts to solve this problem?

Expert replies
by beater » Mon Jan 19, 2009 4:04 pm
In a group of 68 students, each student is registered for at least one of three classes – History, Math and English. Twenty-five students are registered for History, twenty-five students are registered for Math, and thirty-four students are registered for English. If only three students are registered for all three classes, how many students are registered for exactly two classes?
a) 13
b) 10
c) 9
d) 8
e) 7

B
Last edited by beater on Fri Mar 27, 2009 5:05 pm, edited 1 time in total.
Join the discussion
Source: — Problem Solving |

This solution is dedicated to my formula-lover friend Vivek:

A+B+C= (AUBUC)+2(AnBnC)+ [exactly two classes]

25+25+34=68+(2x3)+ X

X=10
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"
Join the discussion

by hksam07 » Mon Jan 19, 2009 5:14 pm
sorry...but why do u have to multiply this part (AnBnC) (three students registered for all three classes) by 2?
Join the discussion

by kanha81 » Fri Mar 27, 2009 5:00 pm
Should not the answer be 13?

total students = H + M + E - [exactly 2 classes] - 3
68 = 25 + 25 + 34 - X - 3
71 = 84 - X
X = 13

[A] what is OA?
Want to Beat GMAT.
Always do what you're afraid to do. Whoooop GMAT
Join the discussion

by Stuart@KaplanGMAT » Fri Mar 27, 2009 9:07 pm
kanha81 wrote:Should not the answer be 13?

total students = H + M + E - [exactly 2 classes] - 3
68 = 25 + 25 + 34 - X - 3
71 = 84 - X
X = 13

[A] what is OA?
Your formula is almost correct, but not quite.

The people in all 3 groups have been counted 3 times, but we only want to count them once. So, instead of subtracting the number of triple group people, we need to subtract twice that number.

So, the answer is:

Total students = H + M + E - [exactly 2 classes] - 2(all 3 classes)

68 = 25 + 25 + 34 - X - 2(3)

68 = 78 - X

X = 10
Image

Stuart Kovinsky | Kaplan GMAT Faculty | Toronto

Kaplan Exclusive: The Official Test Day Experience | Ready to Take a Free Practice Test? | Kaplan/Beat the GMAT Member Discount
BTG100 for $100 off a full course
Join the discussion

by mjjking » Fri Mar 27, 2009 9:11 pm
How do we know whether e have to count them twice or not?
Beat The GMAT - 1st priority
Enter a top MBA program - 2nd priority
Loving my wife: MOST IMPORTANT OF ALL!

REAL THING 1 (AUG 2007): 680 (Q43, V40)
REAL THING 2 (APR 2009): 720 (Q47, V41)
Join the discussion

by Stuart@KaplanGMAT » Fri Mar 27, 2009 9:20 pm
mjjking wrote:How do we know whether e have to count them twice or not?
In the end, we want to count everyone once.

If someone appears in 2 groups, and we add those together, we've counted them twice; accordingly, we need to subtract them once to get a "true" count.

If someone appears in 3 groups, and we add those together, we've counted them three times; accordingly, we need to subtract them twice to get a "true" count.
Image

Stuart Kovinsky | Kaplan GMAT Faculty | Toronto

Kaplan Exclusive: The Official Test Day Experience | Ready to Take a Free Practice Test? | Kaplan/Beat the GMAT Member Discount
BTG100 for $100 off a full course
Join the discussion

by sureshbala » Fri Mar 27, 2009 9:45 pm
When you add 25+25+34 we get 84. But given that total strength is 68. We got an extra of 16 because the people who take exactly two subjects (say X)are counted twice and the number of people who take all the three (say Y) are counted thrice.

Hence x+2Y = 16

Given Y = 3

So X =10

(Note: This result will be evident once you go through the basics of venn diagrams)
Join the discussion