Average
- The average of 100 observations was calculated as 35. It was found later, that one of the observations was misread as 83 instead of 53. The correct average is :
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According to question ,
Difference = 83 – 53 = 30
Incorrect observation > Correct observation∴ Required average = 35 - 30 100
Correct Option: B
According to question ,
Difference = 83 – 53 = 30
Incorrect observation > Correct observation∴ Required average = 35 - 30 = 35 - 0.3 = 34.7 100
- If the difference between the average of x, y and y, z is 12, then the difference between x and z is :
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According to the question,
x + y - y + z = 12 2 2
Correct Option: A
According to the question,
x + y - y + z = 12 2 2 ⇒ X - Z = 12 2
⇒ x – z = 2 × 12 = 24
- The average of the first 7 integers in a series of 13 consecutive odd integers is 37. What is the average of the entire series?
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Given that , Average of 7 consecutive odd integers = 37
∴ Fourth odd number = 37
∴ First odd number = 31
13th odd number = 31 + 24 = 55Correct Option: D
Given that , Average of 7 consecutive odd integers = 37
∴ Fourth odd number = 37
∴ First odd number = 31
13th odd number = 31 + 24 = 55∴ Required average = 31 + 55 = 86 = 43 2 2
- In an examination the average marks obtained by John in English, Maths, Hindi and Drawing were 50. His average marks in Maths, Science, Social Studies and Craft were 70. If the average marks in all seven subjects is 58, his score in maths was
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Here , The average marks obtained by John in English, Maths, Hindi and Drawing = 50.
Average marks in Maths, Science, Social Studies and Craft = 70
The average marks in all seven subjects = 58
According to question ,
Marks in Maths = 50 × 4 + 70 × 4 – 58 × 7
Marks in Maths = 200 + 280 – 406Correct Option: D
Here , The average marks obtained by John in English, Maths, Hindi and Drawing = 50.
Average marks in Maths, Science, Social Studies and Craft = 70
The average marks in all seven subjects = 58
According to question ,
Marks in Maths = 50 × 4 + 70 × 4 – 58 × 7
Marks in Maths = 200 + 280 – 406
Marks in Maths = 480 – 406 = 74
- The average of 9 numbers is 30. The average of first 5 numbers is 25 and that of the last 3 numbers is 35. What is the 6th number?
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According to question,
The average of 9 numbers = 30
Now,The total of 9 numbers = 30 × 9 = 270
The average of first 5 numbers = 25
∴ The total of first 5 numbers = 25 × 5 = 125
and Total of last 3 numbers = 3 × 35 = 105
Required answer = The total of 9 numbers - ( The total of first 5 numbers + Total of last 3 numbers )Correct Option: C
According to question,
The average of 9 numbers = 30
Now,The total of 9 numbers = 30 × 9 = 270
The average of first 5 numbers = 25
∴ The total of first 5 numbers = 25 × 5 = 125
and Total of last 3 numbers = 3 × 35 = 105
Required answer = The total of 9 numbers - ( The total of first 5 numbers + Total of last 3 numbers )
Hence, required answer = 270 – (125 + 105) = 270 – 230 = 40
