Practice MCQ Questions and Answer on Average

11.

The average temperature for Wednesday, Thursday and Friday was 40^{ÃÂÃÂÃÂÃÂ°}C. The average for Thursday, Friday and Saturday was 41ÃÂÃÂÃÂÃÂ° C. If temperature on Saturday was 42ÃÂÃÂÃÂÃÂ° C, what was the temperature on Wednesday?

(A) 39° C
(B) 44° C
(C) 38° C
(D) 41° C

12.

There are three categories of jobs A, B and C. The average salary of the student who got the job of A and B categories is 26 lakh per annum. The average salary of the students who got the job of B and C category is 44 lakh per annum and the average salary of those students who got the job of A and C categories is 34 lakh per annum. The most appropriate (or closet) range of average salary of all the three categories (if it is known that each student gets only one category of jobs i.e. , A, B and C):

(A) lies between 30 and 44
(B) lies between 28 and 34
(C) lies between 34 and 44
(D) lies between 27 and 44

Solution: Let the number of students who got the job of A, B and C categories is a, b and c respectively, Then the total salary, $= \frac{{26 (a + b) + 44 (b + c) + 34 (c + a)}}{2 (a + b + c)}$ $\begin{aligned} = \frac{(60 a + 70 b + 78 c)}{2 (a + b + c)} \\ = \frac{[30 (a + b + c) + (5 b + 9 c)]}{(a + b + c)} \end{aligned}$ = 30 + some positive value Thus, the minimum salary must be Rs. 30 lakh and the maximum salary can not exceed 44, which is the highest of the three

13.

The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is-

(A) 35 years
(B) 40 years
(C) 50 years
(D) None of these

14.

The average annual income (in Rs.) of certain agricultural workers is S and that of other workers is T. The number of agricultural workers is 11 times that of other workers. Then the average monthly income (in Rs.) of all the workers is-

(A) $\frac{S + T}{2}$
(B) $\frac{S + 11 T}{2}$
(C) $\frac{1}{11 S} + 1$
(D) $\frac{11 S + T}{12}$

Solution: Let the number of other workers be x Then, number of agricultural workers = 11x Total number of workers = 12x ∴ Average monthly income $\begin{aligned} = \frac{S \times 11 x + T \times x}{12 x} \\ = \frac{11 S + T}{12} \end{aligned}$

15.

Ten years ago, the ages of the members of a joint family of eight people added up to 231 years. Three years later, one member died at the age of 60 years and a child was born during the same year. After another three years, one more member died, again at 60, and a child was born during the same year. The current average of this eight-member joint family is nearest to-

(A) 21 years
(B) 22 years
(C) 23 years
(D) 24 years

Solution: Sum of the ages of 8 members, 10 years ago = 231 years Sum of the ages of all members, 7 years ago = (231 + 8 × 3 - 60) years = 195 years Sum of the ages of all members, 4 years ago = (195 + 8 × 3 - 60) years = 159 years Sum of the present ages of all 8 members = (159 + 8 × 4) years = 191 years ∴ Current average age = $\frac{191}{8}$ years = 23.8 years $\approx$ 24 years

16.

The average price of 10 books is Rs.12 while the average price of 8 of these books is Rs. 11.75. Of the remaining two books, if the price of one book is 60% more than the price of the other, what is the price of each of these two books?

(A) Rs. 5, Rs.7.50
(B) Rs. 8, Rs. 12
(C) Rs. 10, Rs. 16
(D) Rs. 12, Rs. 14

Solution: Total cost of 10 books = Rs. 120 Total cost of 8 books = Rs. 94 ⇒ The cost of 2 books = Rs. 26 Let the price of each book be x and y. ⇒ x + y = 26 - - - - - -(1) Given that the price of 1 book is 60% more than the other price $\begin{aligned} (\frac{160}{100}) y + y = 26 \\ \Rightarrow y (\frac{160}{100} + 1) = 26 \\ \Rightarrow y (\frac{160 + 100}{100}) = 26 \\ \Rightarrow y = \frac{(26 \times 100)}{260} \\ \Rightarrow y = 10 \\ Substituting y = 10 in (1) we get, \\ x + 10 = 26 \\ x = 16 \end{aligned}$

17.

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 :

(A) $\frac{x^{3} + y^{3}}{x + y}$
(B) xy
(C) $\frac{x^{2} + y^{2}}{x + y}$
(D) xy2 + yx2

Solution: According to the question, Average of x number is y2 ∴ Sum of x number is = xy2 Average of y number is = x2 ∴ Sum of y number is = yx2 Average of all number is = $\frac{x y^{2} + y x^{2}}{x + y}$ = $\frac{x y (x + y)}{x + y}$ = xy

18.

Average of ten positive numbers is $\overset{―}{x}$ . If each number is increased by 10%, then $\overset{―}{x}$ -

(A) Remains unchanged
(B) May decrease
(C) May increase
(D) Is increased by 10%

Solution: $\begin{aligned} \Rightarrow \frac{x_{1} + x_{2} + . . . . . + x_{10}}{10} = \overset{―}{x} \\ \Rightarrow x_{1} + x_{2} + . . . . . + x_{10} = 10 \overset{―}{x} \\ \Rightarrow \frac{110}{100} x_{1} + \frac{110}{100} x_{2} + . . . . . + \frac{110}{100} x_{10} = \frac{110}{100} \times 10 \overset{―}{x} \\ \Rightarrow \frac{\frac{110}{100} x_{1} + \frac{110}{100} x_{2} + . . . . . + \frac{110}{100} x_{10}}{10} = \frac{11}{10} \overset{―}{x} \end{aligned}$ ⇒ Average is increased by 10%

19.

Six numbers are arranged in decreasing order. The average of the first five numbers is 30 and the average of the last five numbers is 25. The difference of the first and the last numbers is

(A) 20
(B) 25
(C) 5
(D) 30

20.

A team of 8 persons joins in a shooting competition. The best marksman scored 85 points. If he had scored 92 points, the average score for the team would have been 84. The number of points the team scored was :

(A) 672
(B) 665
(C) 645
(D) 588

«
1
2
3
4
5
6
7
8
9
10
...
46
47
Next ›
Last »

Indian Polity Mcq IAS GK Question India GK World GK GK questions GK Quiz Biology GK Science GK Physics GK Chemistry GK General Awareness Computer GK Political GK Indian Political GK Economics GK History GK Sports GK Geography GK Teaching Aptitude GK CTET/TET GK B Ed Entrance GK Banking GK SSC GK UPSC GK Indian Army GK Hindi Grammar GK Hindi Grammar MCQ Reasoning questions Bihar GK Rajasthan GK Jharkhand GK MP GK UP GK Chhattisgarh GK Haryana GK HP GK Maharashtra GK Electronics GK Agriculture GK States/Capitals GK Books Name & Author Arthimetic Verbal Reasoning Non Verbal Reasoning English

Practice MCQ Questions and Answer on Average

General Knowledge