Average
- The average of 27 numbers is 60. If one number is changed from 28 to 82, the average is
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Given that , The average of 27 numbers is 60.
If one number is changed from 28 to 82 ,then
Difference of numbers = 82 – 28 = 54∴ Required average = 60 + 54 = 62 27
Second method to solve this question with the help of given formula :
Here, n = 27, m = 60 , b = 28, a = 82New Average = m + (a - b) n
Correct Option: C
Given that , The average of 27 numbers is 60.
If one number is changed from 28 to 82 ,then
Difference of numbers = 82 – 28 = 54∴ Required average = 60 + 54 = 62 27
Second method to solve this question with the help of given formula :
Here, n = 27, m = 60 , b = 28, a = 82New Average = m + (a - b) n New Average = 60 + (82 - 28) 27 New Average = 60 + 54 27
New Average = 62
- A student finds the average of ten 2-digit numbers. While copying numbers, by mistake, he writes one number with its digits interchanged. As a result his answer is 1.8 less than the correct answer. The difference of the digits of the number, in which he made mistake, is
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According to question ,
Difference in average = 1.8
∴ Difference between the number and the number formed by interchanging the digits = 1.8 × 10 = 18 (∴ 53 – 35 = 18)Correct Option: A
According to question ,
Difference in average = 1.8
∴ Difference between the number and the number formed by interchanging the digits = 1.8 × 10 = 18 (∴ 53 – 35 = 18)
∴ Number = 35
∴ Difference of digits = 5 – 3 = 2
- The average of 10 numbers is calculated as 15. It is discovered later on that while calculating the average one number, namely 36, was wrongly read as 26. The correct average is
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Here , The average of 10 numbers = 15 .
While calculating the average one number, namely 36, was wrongly read as 26 ,
Correct total of 10 numbers = 15 × 10 – 26 + 36 = 160∴ Correct average = 160 = 16 10
Second method to solve this question with the help of given formula :
Here, n = 10, m =15 , a = 36, b = 26Correct Average = m + (a - b) n
Correct Option: C
Here , The average of 10 numbers = 15 .
While calculating the average one number, namely 36, was wrongly read as 26 ,
Correct total of 10 numbers = 15 × 10 – 26 + 36 = 160∴ Correct average = 160 = 16 10
Second method to solve this question with the help of given formula :
Here, n = 10, m =15 , a = 36, b = 26Correct Average = m + (a - b) n Correct Average = 15 + (36 - 26) = 15 + 1 = 16 10
- While finding the average of 10 given numbers, a student, by mistake, wrote 64 in place of a number 46 and got his correct average 50. The correct average of the given numbers is :
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According to question ,
Difference of numbers = 64 – 46 = 18Correct average = 50 – 18 10
Correct average = 50 – 1.8 = 48.2
Second method to solve this question with the help of given formula :
Here, n = 10, m = 50 , a = 46, b = 64Correct Average = m + (a -b) n
Correct Option: A
According to question ,
Difference of numbers = 64 – 46 = 18Correct average = 50 – 18 10
Correct average = 50 – 1.8 = 48.2
Second method to solve this question with the help of given formula :
Here, n = 10, m = 50 , a = 46, b = 64Correct Average = m + (a -b) n Correct Average = 50 + (46 - 64) 10 Correct Average = 50 - 18 10
Correct Average = 50 – 1.8 = 48.2
- The mean of 50 observations was 36. It was found later that an observation 48 was wrongly taken as 23. The corrected (new) mean is
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The mean of 50 observations = 36
⇒ The sum of 50 observations = 50 × 36 = 1800The correct mean = 1800 - 23 + 48 50 = 1825 = 36.5 50
Second method to solve this question with the help of given formula :
Here, n = 50, m = 36 , a = 48, b = 23Correct Average = m + (a -b) n
Correct Option: C
The mean of 50 observations = 36
⇒ The sum of 50 observations = 50 × 36 = 1800The correct mean = 1800 - 23 + 48 50 = 1825 = 36.5 50
Second method to solve this question with the help of given formula :
Here, n = 50, m = 36 , a = 48, b = 23Correct Average = m + (a -b) n Correct Average = 36 + (48 - 23) 50 Correct Average = 36 + 25 = 36.5 50
