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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 - If 40 is the average of the four number A, B,C and D . on the other hand 40 is also the average of four numbers A,B,E and F. Find out the following term which must be correct?

Answer : B

Explanation

(A+B+C+D)= (40*4) =160 , (A+B+E+F) = (40*4) =160
 ∴ A+B+C+D = A+B+E+F ⇒ C+D= E+F

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 - 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 - 84 kg is the average weight of 3 people A, B and C. 80 kg is the average if D joins the group. A new man E replaces who have 3kg more weight than D. At that time 79 kg is the average weight of B, C, D and E. What should be the weight of A?

Answer : A

Explanation

A+B+C= (3*84)= 252 kg.     A+B+C+D= (4*80)= 320 kg
weight of D =( 320- 252) =68 kg.   weight of E = (68+3)= 71 kg.
sum of the weight of B+C+D+E= (79*4)= 316 kg ,
sum of the weight of B+C+D = (316-71)=245kg.
Total weight of A = (320- 245 )= 75 kg.

Q 5 - find out the total value of 6 numbers if 45 is the arithmetic mean of 6 numbers.

Answer : D

Explanation

a,b,c,d,e,f is the given 6 numbers  .Then ,
(a+b+c+d+e+f)/6 = 45  = (a+b+c+d+e+f) = 45*6 = 270.
Sum of the given numbers = 270.

Q 6 - 7 is the average of 15 numbers. 6.5 is the average of first 8 numbers and 9.5 is the average of last 8 numbers. What should be the value of middle number?

Answer : A

Explanation

middle number = (8* 6.5) +(8*9.5)-(15*7)
= (52+76- 105) = 23

Q 7 - The average of five numbers is 27. If one number is excluded, the average becomes 25. The excluded number is?

Answer - A

Explanation

Excluded number = (27 x 5) - (25 x 4) = 135 - 100 = 35.

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 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?

Answer - C

Explanation

Let P,Q and R represent their respective monthly incomes. Then we have: 
P + Q = (5050 x 2) = 10100 ...(i)
Q + R = (6250 x 2) = 12500 ...(ii)
P + R = (5200 x 2) = 10400 ...(i)
Adding (i), (ii), (iii) we get : 2(P + Q + R) = 33000 or P + Q + R = 16500 ...(iv)

Subtracting (ii) from (iv), we get P = 4000
Therefore P's monthly income = Rs. 4000.

Q 10 - 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?

Answer - A

Explanation

Sum of the present ages of husband, wife and child = (27 x 3 + 3 x 3) years = 90 years. 
Sum of the present ages of wife and child = (20 x 2 + 5 x 2) years = 50 years 
Therefore Husbands present age = (90 - 50) years = 40 years

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