Average
Exam Duration: 45 Mins Total Questions : 30
The average of 20 numbers is zero. Of them at the most, how many may be greater than zero?
- (a)
0
- (b)
1
- (c)
10
- (d)
19
The average of the first five multiples of 3 is:
- (a)
3
- (b)
9
- (c)
12
- (d)
15
Average=\(\frac { 3\left( 1+2+3+4+5 \right) }{ 5 } =\frac { 45 }{ 5 } =9\)
The average of the first nine prime numbers is :
- (a)
9
- (b)
11
- (c)
\(11{1\over 9}\)
- (d)
\(11{2\over 9}\)
Average=\(\left( \frac { 2+3+5+7+11+13+17+19+23 }{ 9 } \right) =\frac { 100 }{ 9 } =11\frac { 1 }{ 9 } \)
The average of 2, 7, 6 and x is 5 and the average of 18, 1, 6, x and y is 10. What is the value of y?
- (a)
5
- (b)
10
- (c)
20
- (d)
30
If the mean of 5 observation x, x+2, x+4, x+6 and x+8 is 11, then the mean of the last three observation is :
- (a)
11
- (b)
13
- (c)
15
- (d)
17
If the mean of a, b, c is M and ab+bc+ca=0, then the mean of a2, b2, c2 is :
- (a)
M2
- (b)
3M2
- (c)
6M2
- (d)
9M2
The average of the two-digit numbers, which remains the same when the digits interchange their positions, is :
- (a)
33
- (b)
44
- (c)
55
- (d)
66
The average of first 50 natural numbers is :
- (a)
12.25
- (b)
21.25
- (c)
25
- (d)
25.5
The average of 7 consecutive numbers is 20. The largest of these numbers is :
- (a)
20
- (b)
22
- (c)
23
- (d)
24
Out of 9 persons, 8 persons spent Rs. 30 each for their meals. The ninth one spent Rs. 20 more than the average expenditure of all the nine. The total money spent by all of them was :
- (a)
Rs. 260
- (b)
Rs. 290
- (c)
Rs. 292.50
- (d)
Rs. 400.50
Let the average expenditure be Rs. x. Then,
\(9x=8\times 30+\left( x+20 \right) \quad or\quad 9x=x+260\quad or\quad 8x=260\quad or\quad x=32.50\)
\(\therefore \) Total money spent=9x=Rs.(9 \(\times \)32.50) =Rs 292.50
The average of five numbers is 27. If one number is excluded, the average becomes 25. The excluded number is :
- (a)
25
- (b)
27
- (c)
30
- (d)
35
Excluded number = (27 \(\times \)5)-(25\(\times \)4) = 135-100 =35.
The average score of a cricketer for ten matches is 38.9 runs.If the average for the first six matches is 42, then find the average for the last four matches.
- (a)
33.25
- (b)
33.5
- (c)
34.25
- (d)
35
Required average= \(\frac { \left( 38.9\times 10 \right) -\left( 42\times 6 \right) }{ 4 } =\frac { 137 }{ 4 } =34.25\)
A grocer has a sale of Rs. 6435, Rs. 6927, Rs. 6855, Rs. 7230 and Rs.6562 for 5 consecutive months. How much sale must he have in the sixth month so that he gets an average sale of Rs. 6500?
- (a)
Rs. 4991
- (b)
Rs. 5991
- (c)
Rs. 6001
- (d)
Rs. 6991
Total sale for 5 months= Rs.(6435+6927+6855+7230+6562)= Rs.34009.
\(\therefore \) Required sale=Rs[(6500\(\times \)6)-34009]=Rs.(39000-34009)=Rs.4991
In the first 10 overs of a cricket game. the run rate was only 3.2. What should be the run rate in the remaining 40 overs to reach the reach the target of 282 runs?
- (a)
6.25
- (b)
6.5
- (c)
6.75
- (d)
7
Required run rate=\(\frac { 282-(3.2\times 10) }{ 40 } =\frac { 250 }{ 40 } =6.25.\)
Of the four numbers, the first is twice the second, the second is one-third of the third and the third is 5 times the fourth. The average of the number is 24.75. The largest of these number is :
- (a)
9
- (b)
25
- (c)
30
- (d)
None of these
Of the four numbers, whose average is 60, the first is one-fourth of the sum of the last three. The first number is :
- (a)
15
- (b)
45
- (c)
48
- (d)
60.25
The average of 8 numbers in 20. The average of first two numbers is \(15{1\over 2}\) and that of the next three is \(21{1\over 3}\). If the sixth number be less than the seventh and eighth numbers by 4 and 7 respectively, then the eighth number is :
- (a)
18
- (b)
22
- (c)
25
- (d)
27
Average of ten positive numbers is \(\bar { x } \). If each number is increased by 10%, then \(\bar { x } \) :
- (a)
remains unchanged
- (b)
may decrease
- (c)
may increase
- (d)
is increased by 10%
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?
- (a)
40 years
- (b)
42 years
- (c)
48 years
- (d)
50 years
Age of the mother= (12\(\times \)7-7\(\times \)6) years= 42 years.
The average height of 25 boys is 1.4 m. When 5 boys leave the group, then the average height increases by 0.15 m. What is the average height of the 5 boys who leave ?
- (a)
0.8 m
- (b)
0.9 m
- (c)
0.95 m
- (d)
1.05 m
- (e)
UnAvailable Option
The average of 8 men is increased by 2 years when two of them whose ages are 21 years and 23 years are replaced by two new men. The average age of the two new men is :
- (a)
22 years
- (b)
24 years
- (c)
28 years
- (d)
30 years
The average of five consecutive numbers is n. If the next two numbers are also included, the average will :
- (a)
remain the same
- (b)
increase by 1
- (c)
increase by 1.4
- (d)
increase by 2
A cricketer whose bowling average is 12.4 runs per wicket takes 5 wickets for 26 runs and thereby decreases his average by 0.4. The number of wickets taken by him till the last match was :
- (a)
64
- (b)
72
- (c)
80
- (d)
85
Three years ago, the average age of A and B was 18 years. With C joining them, the average age becomes 22 years. How old is C now?
- (a)
24 years
- (b)
27 years
- (c)
28 years
- (d)
30 years
The average age of students of a class is 15.8 years. The average age of boys in the class is 16.4 years and that of the girls is 15.4 years. The ratio of the number of boys to the number of girls in the class is :
- (a)
1 : 2
- (b)
2 : 3
- (c)
3 : 4
- (d)
3 : 5
The average weight of 45 students in a class is 52 kg.Five of them whose average weight is 48 kg leaveable class and other 5 students whose average weight is 54 kg join the class.What is the new average weight (in kg) of the class?
- (a)
\(52\frac{1}{3}\)
- (b)
\(52\frac{1}{2}\)
- (c)
\(52\frac{2}{3}\)
- (d)
None of these
The total of the present ages of A,B,C and D is 96 years. What is B's present age ?
I. The average age of A,B and D is 20 years.
II. The average age of C and D is 25 years.
- (a)
If the data in statement I alone are sufficient to answer the question, while the data in statement II alone are not sufficient to answer the question.
- (b)
If the data in statement II alone are sufficient to answer the question, while the data in statement I alone are not sufficient to answer the question.
- (c)
If the data either in statement I or in Statement II alone are sufficient to answer the question.
- (d)
If the data even in both Statement I and II together are not sufficient to answer the question.
- (e)
If the data in both Statement I and II together are necessary to answer the question.
The average age of P,Q,R and S is 30 years. How old is R ?
I. The sum of ages of P and R is 60 years.
II. S is 10 years younger than R.
- (a)
If the data in statement I alone are sufficient to answer the question, while the data in statement II alone are not sufficient to answer the question.
- (b)
If the data in statement II alone are sufficient to answer the question, while the data in statement I alone are not sufficient to answer the question.
- (c)
If the data either in statement I or in Statement II alone are sufficient to answer the question.
- (d)
If the data even in both Statement I and II together are not sufficient to answer the question.
- (e)
If the data in both Statement I and II together are necessary to answer the question.
The average age of teacher and student in a class is 3 years more than the average age of students. What is the age of the class teacher ?
I. There are 11 students in the class.
II. The average age of teacher and students is 14 years.
- (a)
If the data in statement I alone are sufficient to answer the question, while the data in statement II alone are not sufficient to answer the question.
- (b)
If the data in statement II alone are sufficient to answer the question, while the data in statement I alone are not sufficient to answer the question.
- (c)
If the data either in statement I or in Statement II alone are sufficient to answer the question.
- (d)
If the data even in both Statement I and II together are not sufficient to answer the question.
- (e)
If the data in both Statement I and II together are necessary to answer the question.
In a cricket eleven, the average age of eleven players is 28 years. What is the age of the captain ?
I. The captain is eleven years older than the youngest player.
II. The average age of 10 players, other than the captain is 27.3 years.
III. Leaving aside the captain and the youngest player, the average ages of three groups of three players each are 25 years, 28 years and 30 years respectively.
- (a)
Any two of the three
- (b)
All I, II and III
- (c)
II only or I and III only
- (d)
II and III only
- (e)
None of these