model 5 find new average from error Section-Wise Topic Notes With Detailed Explanation And Example Questions
MOST IMPORTANT quantitative aptitude - 9 EXERCISES
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Basic Average Questions Practice Test, Shortcuts, Tricks, PDF »
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New Average Aptitude MCQ Average of Consecutive Numbers »
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Top 99+ Average Aptitude: Twice, One Third of Numbers MCQ »
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New +99 Average Aptitude MCQ Find nth Average of Numbers »
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99+ Average Aptitude Find New Average from Error MCQ Test »
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Top 99+ Aptitude MCQ Test on Average With Excluded Number »
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Top 99+ Aptitude Average on Ages & Weights MCQ Test Quiz »
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Top Aptitude Average MCQ Find Monthly Income for Average »
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Top 149+ Aptitude Average on Cricket & Exam MCQ Test Quiz »
The following question based on average topic of quantitative aptitude
(a) 210
(b) 200
(c) 180
(d) 240
The correct answers to the above question in:
Answer: (b)
Let the number of candidates be x, then
60x – 45x = 30 × 100
⇒ 15x = 3000
⇒ x = 200
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Read more new average from error Based Quantitative Aptitude Questions and Answers
Question : 1
The average of 20 numbers is calculated as 35. It is dicovered later, that while calculating the average, one number, namely 85, was read as 45. The correct average is
a) 37
b) 36.5
c) 36
d) 37.5
Answer »Answer: (a)
Correct sum of 20 numbers
= 20 × 35 – 45 + 85
= 700 + 40 = 740
∴ Correct average = $740/20$ = 37
Aliter : Using Rule 26,
If average of n numbers is m later on it was found that a number 'a’ was misread as 'b’.
The correct average will be = m +${\text"(a-b)"}/ \text"n"$.
Here, n = 20, m = 35
a = 85, b = 45
Correct mean = m + ${\text"(a - b)"}/\text"n"$
= 35 +${(85 - 45)}/20$
= 35 + 2 = 37
Question : 2
A student, by mistake, wrote 64 in place of 46 as a number at the time of finding the average of 10 given numbers and got the average as 50. The correct average of the numbers is :
a) 48
b) 48.2
c) 49
d) 48.1
Answer »Answer: (b)
Correct sum of numbers
= 10 × 50 – 64 + 46
= 500 – 18 = 482
∴ Correct average = $482/10$ = 48.2
Question : 3
In an examination, the average of marks was found to be 50. For deducting marks for computational errors, the marks of 100 candidates had to be changed from 90 to 60 each and so the average of marks came down to 45. The total number of candidates, who appeared at the examination, was
a) 300
b) 600
c) 150
d) 200
Answer »Answer: (b)
Let total number of candidates be x.
∴ 50x – 30 × 100 = 45x
⇒ 5x = 3000
⇒ x = $3000/5$=600
Question : 4
The average of 25 observations is 13. It was later found that an observation 73 was wrongly entered as 48. The new average is
a) 14
b) 12.6
c) 13.8
d) 15
Answer »Answer: (a)
Difference of two observations = 73 – 48 = 25
∴ New average = 13 + $25/25$=14
Aliter : Using Rule 26,
If average of n numbers is m later on it was found that a number 'a’ was misread as 'b’.
The correct average will be = m +${\text"(a-b)"}/ \text"n"$.
Here, n = 25, m = 13
a = 73, b = 48
Correct Average = m + ${\text"(a-b)"}/ \text"n"n$
= 13 +${(73- 48)}/25$
= 13 + 1 = 14
Question : 5
The average of 9 observations was found to be 35. Later on, it was detected that an observation 81 was misread as 18. The correct average of the observations is :
a) 42
b) 28
c) 45
d) 32
Answer »Answer: (a)
Correct sum of 9 observations
= 9 × 35 – 18 + 81
= 315 + 63 = 378
∴ Required correct average = $378/9$ = 42
Question : 6
The average of 50 numbers is 38. If two numbers, namely 45 and 55 are discarded, the average of the remaining numbers is
a) 37.9
b) 37.5
c) 37.0
d) 36.5
Answer »Answer: (b)
Sum of 50 numbers = 50 × 38 = 1900
Sum of 48 numbers = 1900 – 45 – 55 = 1800
∴ Required average = $1800/48$ = 37.5
GET average PRACTICE TEST EXERCISES
model 1 basic average questions
model 2 average of consecutive numbers
model 3 twice, thrice, one third etc. of numbers
model 4 find nth average from 1st & last number
model 5 find new average from error
model 6 find average of excluded number
model 7 average on ages/weight
model 8 find monthly income
model 9 average on cricket/exam
average Shortcuts and Techniques with Examples
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model 1 basic average questions
Defination & Shortcuts … -
model 2 average of consecutive numbers
Defination & Shortcuts … -
model 3 twice, thrice, one third etc. of numbers
Defination & Shortcuts … -
model 4 find nth average from 1st & last number
Defination & Shortcuts … -
model 5 find new average from error
Defination & Shortcuts … -
model 6 find average of excluded number
Defination & Shortcuts … -
model 7 average on ages/weight
Defination & Shortcuts … -
model 8 find monthly income
Defination & Shortcuts … -
model 9 average on cricket/exam
Defination & Shortcuts …
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