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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 - 68 is the average score scored by the student in a class. 80 is the average of girls marks and 60 is the average score of boys in this class. Find out the percentage of boys in the class?
Answer : D
Explanation
If 100 is the total quantity of the class and x is the number of boys in the class , then the number of girls will be (100-x). 60x+ 80(100-x) = 6800 ⇒ 60x+8000-80x = 6800 = 20x = 1200 ⇒ x =60 So , its proves that that boys percentage in a class is 60%.
Q 3 - Find out the total employee's quantity if the given condition such that Rs. 8500 is the average salary of workers. 10000 Rs. is the average monthly salary of 7 technicians and remaining worker has Rs. 7800 average salary of the month.
Answer : B
Explanation
If x employees working in firm . then (7* 10000)+7800(x-7 )= 8500 = 70000 +7800x-546 00 =8500x ⇒ 700x = 15400 ⇒ x = 22 We find that 22 employees are working in the firm.
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 - With the average of 12.4 takes 5 wickets by use of 26 run. A player has 0.4 downfalls in his average. What should be the number of wicket taken by him before the last match played?
Answer : A
Explanation
x is the number of wickets taken a player before the last match played. Then, (12.4x+26)/(x+5) =12 ⇒ 12.4x+26 =12x+60 ⇒ 0.4x =34 ⇒ 0.4x =34 ⇒ x= 34/0.4 ⇒ x =340/4 = 85. Wickets required = 85.
Q 6 - Rs. 450 is average of 5 shirts and Rs.750 is the average of 4 trousers and 12 pair of shoes average is also Rs.750. Find out the average expenditure per product?
Answer : A
Explanation
sum of the all items = (450*5 +750*4+750*12) = Rs. 14250 Average expenditure per product = Rs. 14250/21 = Rs. 678.21
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 - If the arithmetic mean of seventy-five numbers is calculated, it is 35. If each number is increased by 5, then mean of new number is?
Answer - D
Explanation
A.M. of 75 numbers = 35. Sum of 75 numbers = (75 x 35) = 2625. Total increase = (75 x 5) = 375. Increased sum = (2625 + 375) = 3000. Increased average = 3000⁄75 = 40.
Q 9 - A cricketer has a certain average for 10 innings. In the eleventh inning, he scored 108 runs, thereby increasing his average by 6 runs. His new average is?
Answer - B
Explanation
Let average for 10 innings be z. Then, = 10z + 108⁄11 = 11z + 66 = 10z + 108 = z = 42. New average = (z + 6) = 48 runs.
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