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Quiz: Average

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Number of Questions: 50

Question: 21 -

Zaheer Khan takes 5 wickets for 26  run in the final match due to which his bowling average improves by 2. His old bowling average was 14. Find the total number of wickets after the final match.

Options:

  1. 24

  2. 22

  3. 25

  4. 21

    5. Answer:

    22
    Solution:

    Let number of wickets he has taken before last match = x
    Total runs conceded before last match = 14x

    14x+26x+5 = 12 ⇒14x+26=12x+60      ⇒2x=34                           ⇒x=17

    Total number of wickets after the final match
    =17+5=22

Question: 22 -

The average age of boys in a class is 16 years and that of the girls is 15 years. What is the average age for the whole class?

Options:

  1. 17

  2. Insufficient Data

  3. 15

  4. 16

    5. Answer:

    Insufficient Data
    Solution:

    We do not have the number of boys and girls. Hence we cannot find out the answer.

Question: 23 -

The average of 8 observations was 25.5. It was noticed later that two of those observations were wrongly taken. One observation was 14 more than the original value and the other observation was wrongly taken as 31 instead of 13. What will be the correct average of those 8 observations.

Options:

  1. 22.5

  2. 23.5

  3. 20.5

  4. 21.5

    5. Answer:

    21.5
    Solution:

    Let correct average = x

    Then, correct total =8x

    Obtained total = 8 × 25.5 = 204

    204−14−(31−13)= 8x            ⇒x = 21.5

Question: 24 -

The average of six numbers is x and the average of three of these is y. If the average of the remaining three is z, then

Options:

  1. x = 2y + 2z

  2. None of these

  3. 2x = y + z

  4. x = y + z

    5. Answer:

    2x = y + z
    Solution:

    Average of 6 numbers = x
    => Sum of 6 numbers = 6x

    Average of the 3 numbers = y
    => Sum of these 3 numbers = 3y

    Average of the remaining 3 numbers = z
    => Sum of the remaining 3 numbers = 3z

    Now we know that 6x = 3y + 3z
    => 2x = y + z

Question: 25 -

In an examination, a student's average marks were 63. If he had obtained 20 more marks for his Geography and 2 more marks for his history, his average would have been 65. How many subjects were there in the examination?

Options:

  1. 12

  2. 13

  3. 14

  4. 11

    5. Answer:

    11
    Solution:

    Let the number of subjects = x
    Then, total marks he scored for all subjects = 63x

    If he had obtained 20 more marks for his Geography and 2 more marks for his history, his average would have been 65
    => Total marks he would have scored for all subjects = 65x

    Now we can form the equation as 65x - 63x = additional marks of the student = 20 + 2 = 22
    => 2x = 22
    =>11