Q.1
The mean of 9 observation is 16. One more observation is included and the new mean becomes 17. The 10th observation is :
Q.2
The average weight of first 11 persons among 12 persons is 95 kg. The weight of 12th person is 33 kg more than the average weight of all the 12 persons. The weight of the 12th person is :
Q.3
The average weight of a group of 20 boys was calculated to be 89.4 kg and it was later discovered that one weight was misread as 78 kg instead of 87 kg. The correct average weight is -
Q.4
A batsman in his 12th innings makes a score of 63 runs and there by increases his average score by 2. What is his average after the 12th innings ?
Q.5
Out of 10 teachers of a school, one teacher retires and in place of him a new teacher 25 years old joins. As a result of it average age of the teachers reduces by 3 years. Age of the retired teacher (in years) is -
Q.6
The average of all the odd integers between 2 an 22 is ?
Q.7
The average weight of five persons sitting in a boat is 38 kg. The average weight of the boat and the persons sitting in the boat is 52 kg. What is the weight of the boat ?
Q.8
The average expenditure of a man for the first five months Rs. 1200 and for the next seven months is Rs. 1300. If he saves Rs. 2900 in that years, his monthly average income is -
Q.9
There are two groups A and B of a class, consisting of 42 and 28 students respectively. If the average weight of group A is 25 kg and that of group B is 40 kg, find the average weight of the whole class.
Q.10
The average of x numbers is y2 and the average of y numbers is x2. So, the average of all the numbers taken together is :
Q.11
The average of the first 100 positive integers is -
Q.12
The average age of 11 players of a cricket team decreases by 2 months when two new players are included in the team replacing two players of age 17 years and 20 years. The average age of new players is :
Q.13
In the afternoon, a student read 100 pages at the rate of 60 pages per hour. In the evening, when she was tired, she read 100 more pages at the rate of 40 pages per hour. What was her average rate of reading the pages per hours ?
Q.14
A student finds the average of ten 2 digits numbers. While copying numbers, by mistake, he writes in number with its digits interchanged. As a result his answer is 1.8 less than the correct answer. The difference of digits of the number, in which he made mistake is ?
Q.15
The average of 25 observations is 13. It was later found that an observation 73 was wrongly entered as 48. The new average is -
Q.16
The average marks obtained by 22 candidate in an examination are 45. The average marks of the first 10 candidates is 55 and those of the last eleven is 40. The number of marks obtained by the eleventh candidate is ?
Q.17
The average age of mother and her six children is 12 years, which is reduced by 5 years if the age of mother is excluded. The age of the mother (in years) is :
Q.18
In a class, the average score of girls in an examination is 73 and that of boys is 71. The average score for the whole class is 71.8. Find the percentage of girls :
Q.19
The average age of 9 students and their teacher is 16 years. The average age of the first four students is 19 years and that of the last five is 10 years. The teacher's age is -
Q.20
Total weekly emoluments of the workers of a factory is Rs. 1534. Average weekly emolument of a worker is Rs. 118. The number of workers in the factory is :
Q.21
The mean of 50 numbers is 30. Later it was discovered that two entries were wrongly entered as 82 and 13 instead of 28 and 31. Find the correct mean.
Q.22
Average of n numbers is a. The first number is increased by 2, second one is increased by 4, the third one is increased by 8 and so on. The average of the new numbers is -
Q.23
Average of first five odd multiples of 3 is -
Q.24
The average of 50 numbers is 38. If two numbers, namely 45 and 55 are discarded, the average of the remaining numbers is ?
Q.25
The average of a collection of 20 measurements was calculated to tb 56 cm. But later it was found that a mistake had occurred in one of the measurement which was recorded as 64 cm., but should have been 61 cm. The correct average must be -
Q.26
The average age of 10 children is 9 years 9 months. The average of 9 children is 8 years 11 months. What is the age of the tenth child ?
Q.27
The average weight of 20 students in a class is increased by 0.75 kg when one student of 35 kg replaced by a new student. Weight of the new student (in kg) is :
Q.28
In a class, there are 40 boys and their average age is 16 years. One boy, aged 17 years, leaving the class and another joining, the average age becomes 15.875 years The age of the new boy is :
Q.29
The average of some natural numbers is 15. If 30 is added to the first number and 5 is subtracted from the last number the average becomes 17.5 then the number of natural numbers is -
Q.30
If the average of 6 consecutive even number is 25, the difference between the largest and the smallest number is :
0 h : 0 m : 1 s