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Quiz: Average

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Number of Questions: 50

Question: 41 -

The average of first three numbers is double of the fourth number. If the average of all
the four numbers is 12, find the 4th number

Options:

  1. 18

  2. 16

  3. 20

  4. 48/7

    5. Answer:

    48/7
    Solution:

    (a + b + c) / 3 = 2d
    a + b + c = 6d
    Also, (a + b + c + d) / 4 = 12
    a + b + c + d = 48
    6d + d = 48
    7d = 48
    d = 48 / 7

Question: 42 -

The average monthly salary of the employees of a firm is Rs.60 out of the employees 12 officers get an average of Rs.400 per month and the rest an average of Rs. 56 per month , Find the number of employee

Options:

  1. 1202

  2. 924

  3. 1032

  4. 1156

    5. Answer:

    1032
    Solution:

    Actual average salary of 12 officers = 400
    Total salary of 12 officers = 400 x 12 = 4800
    Average of these 12  officers as a whole =60
    Total salary of 12 officers as a whole = 60 x 12 = 720
    The total salary of rest  = 4800 - 720 = 4080
    Difference in average of the rest of officers  = 60 - 56 = 4
    Rest of the officers ={4080/4}=1020
    Total number of employees = 1020 + 12 = 1032

Question: 43 -

The mean temperature of Monday to Wednesday was 37C and of Tuesday to Thursday was 34C . If the temperature on Thursday was (4/5) th that of Monday, the temperature on Thursday was?

Options:

  1. 34

  2. 36

  3. 37

  4. 35

    5. Answer:

    36
    Solution:

    M +T+W = 37 x 3 =111 – (1)
    T+W+Th = 34x 3= 102
    T+W+4/5M = 102 – (2)
    (1) – (2) gives
      1/5th of temperature on Monday = 111 - 102 =9  
      Temperature on Monday =  45
      Temperature on Thursday =  4/5*45= 36

Question: 44 -

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 ?

Options:

  1. 65

  2. 66

  3. 62

  4. 64

    5. Answer:

    64
    Solution:

    Sum of temperatures on 1st, 2nd, 3rd and 4th days = (58 * 4) = 232 degrees ... (1)
    Sum of temperatures on 2nd, 3rd, 4th and 5th days - (60 * 4) = 240 degrees  ....(2)
    Subtracting (1) From (2), we get :
    Temp, on 5th day  - Temp on 1st day  = 8 degrees.
    Let the temperatures on 1st and 5th days be 7x and 8x degrees respectively.
    Then, 8x - 7x = 8 or x = 8.
    Temperature on the 5th day = 8x = 64 degrees.

Question: 45 -

10 years ago, the average age of a family of 4 members was 24 years. Two children having been born (with age diference of 2 years), the present average age of the family is the same. The present age of the youngest child is :

Options:

  1. 2

  2. 4

  3. 1

  4. 3

    5. Answer:

    3
    Solution:

    Total age of 4 members, 10 years ago = (24 x 4) years = 96 years.
    Total age of 4 members now = [96 + (10 x 4)] years = 136 years.
    Total age of 6 members now = (24 x 6) years = 144 years.
    Sum of the ages of 2 children = (144 - 136) years = 8 years.
    Let the age of the younger child be x years.
    Then, age of the elder child = (x+2) years.
    So, x+(x+2) =8 <=> x=3 
    Age of younger child  =  3 years.