Average of 7 numbers is 28. One of these numbers is 22. 22 is replaced with a new number. New average becomes 30. What is that new number?
Given:
Initial average of 7 numbers = 28
Replaced number = 22
New average of 7 numbers = 30
Formula Used:
Sum = Average × Number of observations
Solution:
Initial total sum of the 7 numbers = 7 × 28 = 196
New total sum of the 7 numbers = 7 × 30 = 210
The increase in the total sum is due to the replacement of 22 with the new number.
Increase in sum = 210 - 196 = 14
Let the new number be x.
x - 22 = 14
x = 22 + 14
x = 36
Final Answer
So the correct answer is (b)
English
80 Questions
160 Marks
60 Mins English English80 Questions160 Marks60 Mins English English20 Questions40 Marks25 Mins EnglishThe average age of 14 persons is 13 years. If the age of 15th persons is added, then the average remains same. What is the age (in years) of the 15th person?
Average age of a group of 16 boys is 24 years. Two boys with ages 19 years and 18 years left the group. One boy with age 43 years joined the group. What is the new average age (in years) of the group?
Average of 6 numbers is P. One number is removed. New average is P + 5. Which number was removed?
Average of 7 numbers is 28. One of these numbers is 22. 22 is replaced with a new number. New average becomes 30. What is that new number?
In a class, the average age of 28 boys is 13 years. Two boys whose ages are 'x' years and 21 years leave the class. If the new average age of the class is 13 years, then what is the value of 'x'?
A set of fifteen numbers has an arithmetic mean of 42 . The mean of the first eight numbers is 39 , while the mean of the last eight numbers is 44 . The value of the eighth number is
A batsman has a certain average after 16 innings. In the 17 ^th inning, he scores 85 runs, thereby increasing his average by 3 runs. What is his new average ?
The average age of Ram and Rohan is 45 years. If Aravind were to replace Ram, the average age would be 44 years; and if Aravind were to replace Rohan, the average age would be 46 years. What are the ages of Ram, Rohan and Aravind, respectively, in years?
The average of 10 observations is 40. It was realised later that an observation was misread as 31 in place of 50. Find the correct average.
The average of 10 observations is 40. It was realised later that an observation was misread as 32 in place of 43. Find the correct average.
Suggested Test Series
Suggested Test Series
