Weighted average is an easy concept that gets test quite often in the quantitative section of the TANCET test.
Let us take a look at a question that requires you to compute the weighted average and then evaluate an alternate shorcut approach to computing the same.
Question
If the average marks scored by 30 students of school A in Class XII board exam is 1072 and that by 20 students of school B is 1084, then what is the average marks scored by the students of the two schools taken together?
1. 1078.6
2. 1076.8
3. 1075.9
4. 1080.2
5. 1077.
Correct Answer
Choice (2). 1076.8
Explanation
The conventional way to solve this question is to find the weighted average of the two marks as show below.
(30*1072 + 20*1084)/(30 + 20)
= (32160 + 21680) / 50
= 53840 / 50
= 1076.8.
As you realize, conceptually there was nothing difficult with solving this question. The only pain point was the calculation. And it might not be possible for most of us to solve this calculation in under 1.2 minutes.
Now let us look at an alternate, shortcut approach to this question.
Step 1: Subtract 1072 from both 1072 and 1084.
Step 2: Compute the weighted average of the resulting numbers. i.e. ,0 and 12
The weighted average of 30 students scoring 0 and 20 students scoring 12
= (30*0 + 20*12) / (30 + 20) = 240 / 50 = 4.8
Step 3: Add 1072 to the weighted average obtained in step 2. i.e., 1072 + 4.8 = 1076.8
Therefore, whenever you have to compute the weighted average of two large numbers, subtract the smaller of the two numbers from both the numbers and then compute the weighted average and then add back the subtracted number to the result.
TANCET 2017 date, syllabus, study materials, coaching, TANCET old question papers and TANCA 2017 counselling guidance
Subscribe to:
Post Comments (Atom)
Popular Posts

Tamil Nadu Common Entrance Examination is conducted by Anna University for admission of students to courses like M. Plan, M. Arch, M. T...

Hello friends… Here is the college wise cut off and expected colleges for a particular cut off based on the analysis of the previous ...

TANCET Non GATE 2013 Estimated BC Rank List. This list is only for reference and not for TANCA Counselling. This rank list reflects the res...

1st SEMESTER : Physics I PH2111 NOV/DEC 20 07 NOV/DEC 20 06 JAN 2010 Mathematics I MA2111 AUG 2008 MAY 2007 Fundamentals Of computers ...

Finally college wise TANCET seat allotment for GATE qualified candidates and Non GATE ( TNACET )Candidates comes Anna University official we...

Candidates who got results of TANCET 2013 are eagerly waiting for the Anna University official rank list. It would be better if the candida...

Third Semester  3rd: INSTRUMENTAL METHOD OF ANALYSIS ( CY 9213 ) NOV/DEC DATA STRUCTURES (CS1151) NOV/DEC 2006 MAY/JUN 2007 NOV/DEC...

Eligibility for M.B.A. Admission A pass in any recognised degree with 10+2+3/4 years pattern or 10+3 years Diploma + 3 years pattern and ha...

DSP: This books are very helpful for TANCET exam preparation. Here you can download all the books free. 1. Integrated circuit 2. DSP BASIC...

Tamil Nadu Common Entrance Test(TANCET) is an entrance examination conducted every year by Anna University on behalf of Tamil Nadu Governmen...
Follow TANCET Updates
TANCET Materials
 About TANCET Exam
 TANCET Exam 2013
 TANCET Exam Syllabus
 TANCET Exam Pattern
 TANCET Exam Eligibility
 TANCET Important Dates
 TANCET Fee Structure
 TANCET Application
 TANCET exam Score
 TANCET Exam Result
 TANCET Exam Books
 TANCET Exam FAQs
 TANCET Preparation Tips
 TANCET Study Materials
 TANCET Question Papers
 TANCET Coaching Centers
 TANCET Exam Tricks
 Why to do M.Tech?
 TANCET Sample Paper
 TANCET Sample Test
 TANCET Videos Courses
 TANCET Discussion Forum
 TANCET Contacts
 Your Feedback
 Certification Exams
 Competitive Exams
 Entrance Exams
 Exam Results
 Edcation Loans
 Scholarships
 Privacy Policy
 Disclaimer
No comments:
Post a Comment