Average
- The average marks obtained by 40 students of a class is 86. If the 5 highest marks are removed, the average reduces by one mark. The average marks of the top 5 students is
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The average marks obtained by 40 students of a class = 86
If the 5 highest marks are removed, the average reduces by one mark , then
Sum of marks of top 5 students = 40 × 86 – 35 × 85
Sum of marks of top 5 students = 3440 – 2975 = 465Correct Option: C
The average marks obtained by 40 students of a class = 86
If the 5 highest marks are removed, the average reduces by one mark , then
Sum of marks of top 5 students = 40 × 86 – 35 × 85
Sum of marks of top 5 students = 3440 – 2975 = 465
∴ Their average = 465 ÷ 5 = 93
- The average marks obtained by 22 candidates in an examination are 45. The average marks of the first 10 candidates are 55 and those of the last eleven are 40. The number of marks obtained by the eleventh candidate is
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Given that , The average marks obtained by 22 candidates in an examination = 45
The average marks of the first 10 candidates = 55 and The average marks of the last eleven = 40
∴ Marks obtained by eleventh candidate = 22 × 45 – (10 × 55 + 11 × 40)Correct Option: B
Given that , The average marks obtained by 22 candidates in an examination = 45
The average marks of the first 10 candidates = 55 and The average marks of the last eleven = 40
∴ Marks obtained by eleventh candidate = 22 × 45 – (10 × 55 + 11 × 40)
Marks obtained by eleventh candidate = 990 – (550 + 440)
Marks obtained by eleventh candidate= 990 – 990 = 0
- 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
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Here , The average of marks was found to be 50
Let total number of candidates be n.
According to question,
∴ 50n – 30 × 100 = 45n
⇒ 50n - 45n = 30 × 100Correct Option: A
Here , The average of marks was found to be 50
Let total number of candidates be n.
According to question,
∴ 50n – 30 × 100 = 45n
⇒ 50n - 45n = 30 × 100
⇒ 5n = 3000
⇒ n = 3000 ÷ 5 = 600
- In an exam, the average marks obtained by the students was found to be 60. After omission of computational errors, the average marks of 100 candidates had to be changed from 60 to 30 and the average with respect to all the examinees came down to 45 marks. The total number of candidates who took the exam, was
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Let the number of candidates be n, then
According to question ,
60n – 45n = 30 × 100
⇒ 15n = 3000Correct Option: A
Let the number of candidates be n, then
According to question ,
60n – 45n = 30 × 100
⇒ 15n = 3000⇒ n = 3000 = 200 15
- The average of 18 observations is recorded as 124. Later it was found that two observations with values 64 and 28 were entered wrongly as 46 and 82. Find the correct average of the 18 observations.
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As per the given details in question ,
Difference in observations = 64 + 28 – 46 – 82 = – 36∴ Correct average = 124 - 36 18 Correct Option: B
As per the given details in question ,
Difference in observations = 64 + 28 – 46 – 82 = – 36∴ Correct average = 124 - 36 = 122 18
