Events & Promotions
|
|
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Apr 2610:00 AM EDT
-11:00 AM EDT
The Target Test Prep course represents a quantum leap forward in GMAT preparation, a radical reinterpretation of the way that students should study. Try before you buy with a 5-day, full-access trial of the course for FREE!
Apr 2711:00 AM EDT
-12:00 PM EDT
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors
Apr 2808:00 AM PDT
-11:00 AM PDT
Whether you are just beginning your MBA journey or fine-tuning your path to a 700+ score, GMAT Day is designed to give you a competitive edge.
29 Sep 2013, 17:14
Kudos
Bookmarks
N
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
(N/A)
Question Stats:
0% (00:00) correct
0%
(00:00)
wrong
based on 0
sessions
History
Date
Time
Result
Not Attempted Yet
Hi guys,
Right now I'm reading the GMAT club math book and I'm having trouble on the advanced overlapping sets problems because no matter how much I read the definitions, I don't understand when to use each formula, which are Total=A+B+C-(sum of 2 group overlaps)+all three+neither and Total=A+B+C-(sum of EXACTLY 2 group overlaps)-2*(all three)+neither. Like what hints do you need to look for in the problem to know when to add all three or to subtract by all three times 2? Thanks for your help!
Right now I'm reading the GMAT club math book and I'm having trouble on the advanced overlapping sets problems because no matter how much I read the definitions, I don't understand when to use each formula, which are Total=A+B+C-(sum of 2 group overlaps)+all three+neither and Total=A+B+C-(sum of EXACTLY 2 group overlaps)-2*(all three)+neither. Like what hints do you need to look for in the problem to know when to add all three or to subtract by all three times 2? Thanks for your help!
30 Sep 2013, 00:18
Kudos
Bookmarks
liff91
If you have 2-group overlap use the first formula and if you ahve EXACTLY 2-group overlap use the second formula.
Example 1:
Workers are grouped by their areas of expertise, and are placed on at least one team. 20 are on the marketing team, 30 are on the Sales team, and 40 are on the Vision team. 5 workers are on both the Marketing and Sales teams, 6 workers are on both the Sales and Vision teams, 9 workers are on both the Marketing and Vision teams, and 4 workers are on all three teams. How many workers are there in total?
Translating:
"are placed on at least one team": members of none =0;
"20 are on the marketing team": M=20;
"30 are on the Sales team": S=30;
"40 are on the Vision team": V=40;
"5 workers are on both the Marketing and Sales teams": MnS=5, note here that some from these 5 can be the members of Vision team as well, MnS is sections d an g on the diagram (assuming Marketing = A, Sales = B and Vision = C);
"6 workers are on both the Sales and Vision teams": SnV=6 (the same as above sections f an g);
"9 workers are on both the Marketing and Vision teams": MnV=9.
"4 workers are on all three teams": MnSnV=4, section 4.
Question: Total=?
Applying first formula as we have intersections of two groups and not the number of only (exactly) 2 group members:
\(Total=M+S+V-(MnS+MnV+SnV)+MnSnV+Neither=20+30+40-(5+6+9)+4+0=74\).
Answer: 74. Discuss this question HERE.
Example 2:
Each of the 59 members in a high school class is required to sign up for a minimum of one and a maximum of three academic clubs. The three clubs to choose from are the poetry club, the history club, and the writing club. A total of 22 students sign up for the poetry club, 27 students for the history club, and 28 students for the writing club. If 6 students sign up for exactly two clubs, how many students sign up for all three clubs?
Translating:
"Each of the 59 members in a high school class is required to sign up for a minimum of one and a maximum of three academic clubs": Total=59, Neither=0 (as members are required to sign up for a minimum of one);
"22 students sign up for the poetry club": P=22;
"27 students for the history club": H=27;
"28 students for the writing club": W=28;
"6 students sign up for exactly two clubs": (sum of EXACTLY 2-group overlaps)=6, so the sum of sections d, e, and f is given to be 6, (among these 6 students there are no one who is a member of ALL 3 clubs)
Question:: "How many students sign up for all three clubs?" --> \(PnHnW=g=?\)
Apply second formula: \(Total=P+H+W -(sum \ of \ EXACTLY \ 2-group \ overlaps)-2*PnHnW + Neither\) --> \(59=22+27+28-6-2*x+0\) --> \(x=6\).
Answer: 6. Discuss this question HERE.
There are 9 more examples discussed here: advanced-overlapping-sets-problems-144260.html
Hope this helps.
