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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 - What should be the average of 5 number consecutive odd numbers if the numbers are A,B,C,D and E?

Answer : B

Explanation

Average = a+(a+2)+(a+4)+(a+6)+(a+8)/5 = (5a+20)/ 5 = (a+4)

Q 2 - 28 is the average of 3 numbers. Find out the value of third number if the given condition is such that the second number have the double value in the comparison of first number and third number have 4 times value of first number?

Answer : A

Explanation

If x is the value of third number.
Then  the value of second number is x/2 , if x/2 is the value of second number then the value of first number will be 1/2 . x/2 = x/4.
Total sum of three number = (3*28) =84
∴ x+x/2+x/4 = 84 ⇒ 7x/4 = 84 ⇒ x= (84*4)/7 = 48
So, its proves that the value of the third number is 48.

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 - Find out the average speed of the journey if with the speed of 6km/hr covers half distance and remaining half covers by the speed of 3 km/hr.

Answer : B

Explanation

Average speed = 2xy / (x+y)km/hr = 2*6*3/ (6+3)km/hr = 4km/hr

Q 5 - 15 is the average weight of 19 students if a new student add then the average weight of the class is 14.8 kg. Find out the weight of the new join student?

Answer : B

Explanation

19 students have  total sum of the weight = (15*19) =285 kg.
20 students have total sum of the weight = (14.8*20)= 296 kg.
Weight of the new student = 296- 285 = 11 kg.

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 - 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 be have in the sixth month so that he gets an average sale of Rs. 6500?

Answer - D

Explanation

Total sale for 5 months = Rs. (6435 + 6927 + 6855 + 7230 + 6562) = Rs. 34009. 
Therefore Required sale = Rs. [(6500 6) - 34009] = Rs. (39000 - 34009) = Rs. 4491

Q 8 - The average temperature of the town in the first four days of a month was 58 degrees. The average for the second, third, fourth and fifth days was 60 degrees. If the temperatures of the first and fifth days were in the ratio 7:8, then what is the temperature on the fifth day?

Answer - A

Explanation

Sum of temperature on 1st, 2nd, 3rd and 4th days = (58 x 4) = 232 degrees ...(i) 
Sum of temperature on 2nd , 3rd 4th and 5th days = (60 x 4) = 240 degrees ...(ii) 
Subtracting (i) from (ii) we get: 
Temp on 5th day - temp on 1st day = 8 degrees 
Let the temperature on 1st and 5th days be 7z and 8z degrees respectively. 

Then, 8z - 7z = 8 or z = 8. 
Therefore Temperature on 5th day = 8z = 64 degrees.

Q 9 - The average weight of A,B and C is 45 kg. If the average weight of A and B be 40kg and that of B and C be 43kg, then the weight of B is:?

Answer - A

Explanation

Let A,B and C represent their respective weights. Then we have: 
A + B + C = (45 x 3) = 135 ...(i)
A + B = (40 x 2) = 80 ...(ii)
B + C = (43 x 2) = 86 ...(i)
Adding (ii), (iii) we get : A + 2B + C = 166  ...(iv)

Subtracting (ii) from (iv), we get B = 31 
∴ B's weight = 31kg.

Q 10 The arithmetic mean of the scores of a group of students in a test was 52. The brightest 20% of them secured a mean score of 80 and the dullest 25% a mean score of 31. The mean score of remaining 55% is?

Answer - A

Explanation

Let the required mean score be z. Then, 

20 x 80 + 25 x 31 + 55 x z = 52 x 100 
1600 + 775 + 55z = 5200 

55z = 2825 = x - 51.40

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