Q.1
The average weight of 8 men is increased by 1.5 kg when one of the men, who weight 65 kg is replaced by a new man. The weight of the new man is-
Q.2
The average age of the mother and her six children is 12 years which is reduced by 5 years if the age of the mother is excluded. How old is the mother ?
Q.3
The average age of the boys in a class is 16 years and that of the girls is 15 years. The average age for the whole class is-
Q.4
The average of two numbers is XY. If one number is X, the other is-
Q.5
The average weight of a class of 24 students is 35 kg. If the weight of the teacher be included, the average rises by 400 g. The weight of the teacher is -
Q.6
In a school with 600 students, the average age of the boys is 12 years and that of the girls is 11 years. If the average of the school is 11 years 9 months, then the average the number of girls in the school is :
Q.7
The arithmetic mean of the scores of a group of students in a test was 52. The brightest 20% of them secured a mean score of 80 and the dullest 25% a mean score of 31. The mean score of remaining 55% is-
Q.8
Total expenses of a boarding house are partly fixed and partly varying linearly with the number of boarders. The average expense per boarder is Rs. 700 when there are 25 boarders and Rs. 600 when there are 50 boarders. What is the average expense per boarder when there are 100 boarders?
Q.9
Amount five people with monthly income (in Rs.) 15000, 26000, 16000, 19000, 50000, how many will have income less than the mean income of five people?
Q.10
In a primary school the average weight of male students is 65.9 kg and the average weight of female students is 57 kg. If the average weight of all the students ( both male and female ) is 60.3 kg and the number of male students in the school is 66, what is the number of female students in the school?
Q.11
The average age of an adult class is 40 years. 12 new students with an average age of 32 years join the class, thereby decreasing the average by 4 years. The original strength of the class was-
Q.12
The average of the first five multiples of 3 is-
Q.13
If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55 and 60, then the average marks of all the students is :
Q.14
Find the average of cubes of first 49 positive integers.
Q.15
If the arithmetic mean of 0, 5, 4, 3 is a, that of -1, 0, 1, 5, 4, 3 is b and that of 5, 4, 3 is c, then the relation between a, b, and c is
Q.16
The average monthly income of P and Q is Rs. 6000; that of Q and R is Rs. 5250; and that P and R is Rs. 5500. What is P’s monthly income?
Q.17
The average weight of a group of 75 girls was calculated as 47 kgs. It was later discovered that the weight of one of the girls was read as 45 kgs. Whereas her actual weight was 25 kgs. What is the actual average weight of the group of 75 girls? ( Rounded off to two digits after decimal).
Q.18
The average of X1, X2 and X3 is 14. Twice the sum of X2 and X3 is 30. What is the value of X1?
Q.19
In a family of 5 members, the average age at present is 33 years. The youngest member is 9 years old. The average age of the family just before the birth of the youngest members was :
Q.20
A cricketer whose bowling average is 24.85 runs per wickets, takes 5 wickets for 52 runs in next inning and thereby decreases his average by 0.85. The number of wickets taken by him till the last match was :
Q.21
The average of 8 numbers is 20. The average of first two numbers is $$15\frac{1}{2}$$ and that of the next three is $$21\frac{1}{3}$$ . If the sixth number be less than the seventh and eighth numbers by 4 and 7 respectively, them the eighth number is :
Q.22
The average age of a class of 39 students is 15 years. If the age of the teacher is included, then the average increases by 3 months. Find the age of the teacher.
Q.23
Find the average of the following sets of scores:
385, 441, 876, 221, 536, 46, 291, 428
Q.24
If 25a + 25b = 115, what is the average of a and b?
Q.25
There are 50 students in a class. Their average weight is 45 kg. When one student leaves the class the average weight reduces by 100 g. What is the weight of the student who left the class ?
Q.26
The mean of 20 items is 55. If two items 45 and 30 are removed, the new mean of the remaining items is :
Q.27
The average of six numbers is 32. If each of first three numbers is increased by 2 and each of the remaining three numbers is decreased by 4, then the new average is ?
Q.28
Average weight of 25 persons is increased by 1 kg when one person weighing 60 kg is replaced by a new person. Weight of new the person is-
Q.29
The average of n numbers x1, x2.....xn is $$\overline x $$ .Then the value of $$\sum\limits_{i\, = \,1}^n {} \left( {{x_i} - \overline x } \right)$$   is equal to -
Q.30
A library has an average number of 510 visitors on sunday and 240 on other days. The average number of visitors per day in a month of 30 day beginning with sunday is -
0 h : 0 m : 1 s