Average


  1. The average of 10 numbers is 7. If each number is multiplied by 12, then the average of the new set of numbers will be









  1. View Hint View Answer Discuss in Forum

    As we know that If each number is multiplied by a certain number, then the average is also multiplied by that number.
    Given , The average of 10 numbers = 7

    Correct Option: D

    As we know that If each number is multiplied by a certain number, then the average is also multiplied by that number.
    Given , The average of 10 numbers = 7
    ∴ Required average = 7 × 12 = 84


  1. The average weight of five persons sitting in a boat is 38 kg. The average weight of the boat and the persons sitting in the boat is 52 kg. What is the weight of the boat ?









  1. View Hint View Answer Discuss in Forum

    Given that , The average weight of five persons sitting in a boat = 38 kg.
    Sum of weight of five persons = 5 × 38 = 190
    The average weight of the boat and the persons sitting in the boat = 52 kg.
    Sum of weight of the boat and five persons = 6 × 52 = 312

    Correct Option: B

    Given that , The average weight of five persons sitting in a boat = 38 kg.
    Sum of weight of five persons = 5 × 38 = 190
    The average weight of the boat and the persons sitting in the boat = 52 kg.
    Sum of weight of the boat and five persons = 6 × 52 = 312
    ∴ Weight of the boat = Sum of weight of the boat and five persons – Sum of weight of five persons
    Weight of the boat = 312 – 190 = 122 kg



  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


  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.









  1. View Hint View Answer Discuss in Forum

    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. In a certain year, the average monthly income of a person was ₹ 3,400. For the first eight months of the year, his average monthly income was ₹ 3,160 and for the last five months, it was ₹ 4,120. His income in the eighth month of the year was









  1. View Hint View Answer Discuss in Forum

    Given that , average income of a person = ₹ 3,400
    Sum of annual income of a person = ₹ ( 3,400 x 12 )
    Sum of first eight month income of a person = ₹ ( 3160 x 8 )
    Sum of last five month income of a person = ₹ ( 5 × 4120 )
    ∴ Person’s income in the eighth month = (3160 × 8 + 5 × 4120 – 12 × 3400)

    Correct Option: B

    Given that , average income of a person = ₹ 3,400
    Sum of annual income of a person = ₹ ( 3,400 x 12 )
    Sum of first eight month income of a person = ₹ ( 3160 x 8 )
    Sum of last five month income of a person = ₹ ( 5 × 4120 )
    ∴ Person’s income in the eighth month = (3160 × 8 + 5 × 4120 – 12 × 3400)
    Person’s income in the eighth month = (25280 + 20600 – 40800) = 5080