# Aptitude - Averages Online Quiz

Following quiz provides Multiple Choice Questions (MCQs) related to **Averages**. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using **Show Answer** button. You can use **Next Quiz** button to check new set of questions in the quiz.

### Answer : B

### Explanation

Up to 100 all odd number have the sum = (1+3+5+7+……+99) = (1+99)+(3+97)+(5+95)+... Upto 25 terms = 100+100+100+... upto 25 terms = 2500 Average = 2500/50 = 50

Q 2 - 30 is the mean find of 100 items. In the calculation of mean two mistakes are done one mistake is 32 take in the place of 12 and for the same 23 take in the place of 11. What should be the actual mean with the calculation of the correct items?

### Answer : D

### Explanation

Sum of all the items = (100*30)= 3000 Correct sum = (3000+23- 32-11) =2990 Correct mean = 2990/100 = 29.90

Q 3 - A class has 24 students. If 18 year old boys left the school and one new boy join the school in that situation the average decrease by 1 month. Find out the age of new boy?

### Answer : A

### Explanation

Downfall in the total age =( 24*1 )= 24 months =2 years The age of the new boy = 18- 2 = 16 years.

Q 4 - A hostel have 35 students if 42 student became in the hostel then expenditure on per student increase and became Rs. 42 per head while Rs. 1 reduce in the average expenditure. Find out the expenditure per day at the present time?

### Answer : D

### Explanation

If x is the original expenditure , then x/35- (x+42)/42 = 1 =. 6x -5(x+42)= 210 ⇒ x= 420 ∴ original expenditure = Rs. 420

Q 5 - N is average of 5 consecutive natural numbers if we add 2 upcoming numbers then what should be the seven number averages?

### Answer : A

### Explanation

x, x+1, x+2, x+3 and x+4 is the 5 natural consecutive numbers. Then , x+(x+1)+(x+2)+(x+3)+(x+4)= 5n ⇒ 5x+10=5n ⇒ x = 5(n-2)/5 = (n-2) ∴ 7 consecutive natural numbers are (n-2),(n-1), n,(n+1), (n+2),(n+3) Average of 7 consecutive natural numbers =( 7n+1/7 ) = (n+1) ∴ average increase by 1.

Q 6 - Find out the number of papers in exams if 63 is the average marks in exams.65 marks will be the average if 20 marks obtained by him in geography and 22 marks in History.

### Answer : A

### Explanation

let there be n papers. Sum of marks of all papers = 63n 65-63n = (20+2) ⇒ 2n = 22 ⇒ n =11 Hence, its proves that the 11 papers held in exams.

Q 7 - 16 children are to be divided into two groups A and B of 10 and 6 children. The average percent marks obtained by the children of group A is 75 and the average percent marks of all the 16 children is 76. What is the average percent marks of children of group B?

**Answer - A**

**Explanation**

Required average =^{(76 x 16) - (75 x 10)}⁄_{6}=^{1216 - 750}⁄_{6}=^{466}⁄_{6}^{233}⁄_{3}= 77^{2}⁄_{3}

Q 8 - Average of ten positive numbers is ‾z. if each number is increased by 10%, then ‾z?

**Answer - B**

**Explanation**

‾z is increased by 10%.

Q 9 - The average age of 36 students in a group is 14 years. When teacher's age is included to it, the average increases by one. What is the teacher's age in years?

**Answer - D**

**Explanation**

Age of the teacher = (37 x 15 - 36 x 14) years = 51 years.

Q 10 - The average weight of 3 men A, B, C is 84 kg. Another man D joins the group and the average now becomes 80kg. If another man E, whose weight is 3 kg more than that of D, replaces A, then the average weight of B, C, D, E becomes 79kg. The weight of A is?

**Answer - B**

**Explanation**

Let A, B, C, D and E represent their respective weights. Then, A + B + C = (84 x 3) = 252 kg, A + B + C + D = (80 x 4) = 320 kg. D = (320 - 252)kg = 68 kg, E = (68 + 3)kg = 71 kg. B + C + D + E = (79 x 4) = 316 kg Now, (A + B + C + D) - (B + C + D + E) = (320 - 316)kg = 4 kg A - E = 4 A = ( 4 + E ) = 75 kg.