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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 - N2 is the average of m numbers and that of n number is m2, find the average of (m+n) numbers is ?
Answer : D
Explanation
Total of (m+n) numbers = (mn2+nm2)= mn(m+n) Average of numbers( m+n) = mn(m+n)/ (m+n) = mn
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 - The students who leave the school find out the average of their marks if 50 is the average of their marks if 50 is the average of 28 students. Condition is given that 55 is the average marks of 20 students.
Answer : A
Explanation
28 students have total marks = ( 28*50)= 1400 20 students have total marks = (55* 20) =1100 Total of 8 those students who leaves the school = 1400- 1100 = 300 Required average = 300/8 = 37.5
Q 5 - What should be the largest number if first number is the half of the second number and third number is 1/3 of the second number? 44 is the average of three numbers?
Answer : A
Explanation
if x is the third number , then second number = 3x ∴ first number = 3x/2 Average =1/3 (3x/2+3x+x) ⇒ (11x/6) =44 ⇒ 11x=264 ⇒ x = 24 Hence, the second number (24*3)=72 is the largest number.
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 age of 35 students in class is 16 years. The average age of 21 students is 14. What is the average age of remaining 14 students?
Answer - B
Explanation
Sum of the ages of 14 students = (16 x 35) - (14 x 21) = 560 - 294 = 266 Therefore Required average = 266⁄14 = 19years.
Q 8 - A pupil's marks were wrongly entered as 83 instead of 63. Due to that the average marks for the class got increased by half. The number of pupils in the class is?
Answer - D
Explanation
Let there be z pupils in the class. Total increase in marks = z x 1⁄2 = z⁄2 Therefore z⁄2 = (83 - 63) = z⁄2 = 20 z = 40.
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 = 2370⁄45kg = 532⁄3kg
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