Average


  1. The average marks of a class of 35 children is 35. The marks of one of the students, who got 35, was incorrectly entered as 65. What is the correct average of the class?









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    According to question ,
    Total correct marks of 35 children = 35 × 35 + 35 – 65 = 1225 – 30 = 1195

    Required average =
    1195
    = 34.14
    35

    Second method to find the required average ,
    Diffference = – 65 + 35 = – 30

    Correct Option: B

    According to question ,
    Total correct marks of 35 children = 35 × 35 + 35 – 65 = 1225 – 30 = 1195

    Required average =
    1195
    = 34.14
    35

    Second method to find the required average ,
    Diffference = – 65 + 35 = – 30
    Required average = 35 –
    30
    35

    Required average = 35 – 0.857 = 34.143


  1. The average weight of 15 oarsmen in a boat is increased by 1.6 kg when one of the crew, who weighs 42 kg is replaced by a new man. Find the weight of the new man (in kg).









  1. View Hint View Answer Discuss in Forum

    Here, N = 15, T = 42, t = 1.6
    We can find required answer with the help of given formula ,
    Weight of new oarsman = ( N + T × t )
    Weight of new oarsman = (42 + 15 × 1.6) kg.

    Correct Option: C

    Here, N = 15, T = 42, t = 1.6
    We can find required answer with the help of given formula ,
    Weight of new oarsman = ( N + T × t )
    Weight of new oarsman = (42 + 15 × 1.6) kg.
    ∴ Weight of new oarsman = (42 + 24) kg. = 66 kg.



  1. The average of all the numbers between 6 and 50 which are divisible by 5 is









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    Given , Numbers are : 10, 15, 20, 25, 30, 35, 40, 45
    Sum of given numbers = 220

    Average =
    Sum of given numbers
    Total numbers

    Correct Option: A

    Given , Numbers are : 10, 15, 20, 25, 30, 35, 40, 45
    Sum of given numbers = 220

    Average =
    Sum of given numbers
    Total numbers

    Average =
    220
    8

    Average = 27.5


  1. The average of 8 numbers is 27. If each of the numbers is multiplied by 8, find the average of new set of numbers.









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    Given , The average of 8 numbers = 27
    If each item is multiplied by 8, their average gets multiplied by 8.
    ∴ Required average = 8 × The average of 8 numbers

    Correct Option: D

    Given , The average of 8 numbers = 27
    If each item is multiplied by 8, their average gets multiplied by 8.
    ∴ Required average = 8 × The average of 8 numbers
    Required average = 8 × 27 = 216



  1. The average monthly salary of all the employees in an industry is ₹ 12,000. The average salary of male employees is ₹ 15,000 and that of female employees is ₹ 8,000. What is the ratio of male employees to female employees ?









  1. View Hint View Answer Discuss in Forum

    Let Male employees = p
    Female employees = q
    ∴ (p + q) 12000 = p × 15000 + q × 8000
    ⇒ (p + q) × 12 = 15p + 8q
    ⇒ 12p + 12q = 15p + 8q
    ⇒ 3p = 4q

    Correct Option: C

    Let Male employees = p
    Female employees = q
    ∴ (p + q) 12000 = p × 15000 + q × 8000
    ⇒ (p + q) × 12 = 15p + 8q
    ⇒ 12p + 12q = 15p + 8q
    ⇒ 3p = 4q

    p
    =
    4
    q3

    ⇒ p : q = 4 : 3