Practice MCQ Questions and Answer on Average

131.

The following table shows the number of working hours and the number of employees employed in a small scale industry

No. of working hours	No. of employees
3 - 5	7
5 - 7	10
7 - 9	18
9 - 11	57
11 - 13	14
13 - 15	8

The average number of working hours of an employee is

(A) 8.5
(B) 9.5
(C) 10.5
(D) None of these

Solution: We have : Mean working hours 4 6 8 10 12 14 No. of employees 7 10 18 57 14 8 Sum of working hours of all the employees = (4 × 7 + 6 × 10 + 8 × 18 + 10 × 57 + 12 × 14 + 14 × 8) = (28 + 60 + 144 + 570 + 168 + 112) = 1082 Total number of employees = (7 + 10 + 18 + 57 + 14 + 8) = 114 ∴ Average number of working hours = $(\frac{1082}{114})$ = 9.49 $\approx$ 9.5

132.

The average of the first 100 positive integers is -

(A) 100
(B) 51
(C) 50.5
(D) 49.5

Solution: According to the question, As we know that average of 'n' positive integer is = $\frac{n (n + 1)}{2 \times n}$ = $\frac{(n + 1)}{2}$ Here n = 100 ∴ $\frac{100 + 1}{2}$ = $\frac{101}{2}$ = 50.5

133.

There are five boxes in a cargo hold. The weight of the first box is 200 kg and the weight of the second box is 20% more than the weight of third box, whose weight is 25% more than the first boxÃÂÃÂÃÂÃÂ¢ÃÂÃÂÃÂÃÂs weight. The fourth box at 350 kg is 30% lighter than the fifth box. The difference in the average weight of the four heaviest boxes and the four lightest boxes is-

(A) 37.5 kg
(B) 51.5 kg
(C) 75 kg
(D) 112.5 kg

Solution: Weight of first box = 200 kg Weight of third box = 125 % of 200 kg = 250 kg Weight of second box = 120% of 250 kg = 300 kg Weight of fourth box = 350 kg Let the weight of fifth box be x kg Then, 70% of x = 350 kg $\begin{aligned} \Rightarrow x = (\frac{350 \times 100}{70}) \\ \Rightarrow x = 500 kg \end{aligned}$ . Average weight of four heaviest boxes $\begin{aligned} = (\frac{500 + 350 + 300 + 250}{4}) kg \\ = 350 kg \end{aligned}$ Average weight of four lightest boxes $\begin{aligned} = (\frac{200 + 250 + 300 + 350}{4}) kg \\ = 275 kg \end{aligned}$ ∴ Required difference = (350 - 275) = 75 kg

134.

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 -

(A) 36 years
(B) 34 years
(C) 30 years
(D) 28 years

135.

The average monthly income of P and Q is Rs. 5050. The average monthly income of Q and R is Rs. 6250 and the average monthly income of P and R is Rs. 5200. The monthly income of P is:

(A) 3500
(B) 4000
(C) 4050
(D) 5000

136.

The average of marks in Mathematics for 5 students was found to do 50. Later, it was discovered that in the case of one student the marks 48 were misread as 84. The correct average is :

(A) 40.2
(B) 40.8
(C) 42.8
(D) 48.2

Solution: According to the question, Correct average $\begin{aligned} = \frac{5 \times 50 + 48 - 84}{5} \\ = \frac{250 - 36}{5} \\ = \frac{214}{5} \end{aligned}$ = 42.8

137.

The average weight of 45 students in a class is 52 kg. Five of them whose average weight is 48 kg leave the 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

Solution: Sum of the weights of the students after replacement = [(52 × 45) - (48 × 5) + (54 × 5)] kg = 2370 kg ∴ New average = $(\frac{2370}{45})$ kg = $52 \frac{2}{3}$ kg

138.

The average weight of 3 men, A, B and C is 84 kg. Another man D joins the group and the average now becomes 80 kg. If another man E whose weight is 3 kg more than that of D, replaces A then the average weight of B, C, D and E becomes 79 kg. What is the weight of A ?

(A) 70 kg
(B) 72 kg
(C) 75 kg
(D) 80 kg

139.

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

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

Solution: Let the total score be x $\begin{aligned} ∴ \frac{x + 92 - 85}{8} = 84 \\ \Rightarrow x + 7 = 672 \\ \Rightarrow x = 665 \end{aligned}$

140.

The average of the ages of Sumit, Krishna and Rishabh is 43 and the average of the ages of Sumit, Rishabh and Rohit is 49. If Rohit is 54 years old, what is KrishnaÃÂÃÂÃÂÃÂ¢ÃÂÃÂÃÂÃÂs age?

(A) 24 years
(B) 36 years
(C) 45 years
(D) Cannot be determined

«
1
2
...
11
12
13
14
15
16
17
...
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