# 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.

Q 1 - Find out the average of A and B if the given value of 16A+ 16B = 48

### Answer : A

### Explanation

16a+16b = 48 ⇒ 16(a+b) = 48 ⇒ (a+b) = 3 So, we have a and b average is (a+b)/2 = 3/2 = 1.5

Q 2 - 23 is the average of 3 friends if we add 1 more person then the value of average will be same or no change. Find out the age of the new person?

### Answer : D

### Explanation

3 friends have the sum of the ages = (3*23)= 69 ...(i) 4 friend have the sum of the ages = (4*23)=92 ...(ii) Difference between the (i) and (ii) is the age of the new person. We find that the age of the new person is (92-69)= 23 years.

Q 3 - 38.6°C is the average temperature of 4 first day of the week while 40.3°C is the average of last 4 days in a week. Find out the temperature on Thursday if 39.1°C is average of whole week?

### Answer : C

### Explanation

M+T+W+Th = (38.6*4)= 154.4 ...(i) T+W+Th+F = (40.3*4) =161.2 ...(ii) M+T+W+Th+F+S+Su =(39.1*7) =273.7 ...(iii) (i)+(ii) –(iii) we find that , (154.4+161.2- 272.7) =41.9°C ∴ 41.9 °C was the temperature on Thursday.

Q 4 - What should be the age difference between new man and the old members if interchange with new men with old men then the average age of 5member as he was before the period of 3 year has no change at the present time?

### Answer : A

### Explanation

Sum of the increment during the period of 3 years =(5*3) = 15 Years. ∴ old and new man have the age difference between them = 15 years.

Q 5 - 40 year is the average of the class. 32 years is the average of the class if 12 new students also add in this class. Find out the number of students in the class?

### Answer : D

### Explanation

x is the strength of the class. 40x+12*32 = 36* (x+12) ⇒ 4x =(432- 384) = 48 ⇒ x = 12 ∴ original strength = 12

Q 6 - Drinks were done by 6 persons. Out of them 5 person paid 32 Rs. each, Rs. 80 more paid by the 6th person in the comparison of average expenditure of all. Find out the total amount paid by 6 persons?

### Answer : A

### Explanation

if x is the average expenditure of 6 person. (32*5)+(x+80)= 6x = 5x = (160+80) = 5x= 240 ⇒ x = 48 Total expenditure = 48*6 =288 Rs.

Q 7 - 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% and more than the price of the other, what is the price of each of these two books?

**Answer - C**

**Explanation**

Total price of the two books = Rs. [(12 x 10) - (11.75 x 8)] = Rs. (120 - 94) = Rs. 26. Let the price of one book be Rs. z. Then, the price of other book = Rs. (z + 60% of z) = Rs. ( z +^{3z}⁄_{5}) = Rs.^{8z}⁄_{5}So, z +^{8z}⁄_{5}= 26 = 13z = 130 = z = 10. Therefore The price of the two books are Rs. 10 and Rs. 16.

Q 8 - Of the three numbers, the first is twice the second and the second is twice of the third. The average of the reciprocal of the numbers is ^{7}_{72}?

**Answer - B**

**Explanation**

Let the third number be z. Then, second number = 2z. First number = 4z. Therefore^{1}⁄_{z}+^{1}⁄_{2z}+^{1}⁄_{4z}=^{7}⁄_{72}x 3^{7}⁄_{4z}=^{7}⁄_{24}or 4z = 24 or z = 6 So, the number are 24, 12 and 6.

Q 9 - The average weight of 45 students in a class is 52kg. Five of them whose average weight is 48 kg leave the class and other 5 students whose average weight is 54kg join the class. What is the new average weight (in kg) of the class?

**Answer - A**

**Explanation**

Sum of the weights of the students after replacement. = [(52 x 45) - (48 x 5) + (54 x 5)] kg = 2370kg. Therefore, new Average =^{2370}⁄_{45}kg = 53^{2}⁄_{3}kg

Q 10 - 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?

**Answer - B**

**Explanation**

Let the ratio be k : 1. then, k x 16.4 + 1 x 15.4 = (k + 1) x 15.8 (16.4 - 15.8) k = (15.8 - 15.4) k =^{0.4}⁄_{0.6}=^{2}⁄_{3}