hamburger menu
All Coursesall course arrow
adda247
reward-icon
adda247
    arrow
    arrow
    arrow
    If the length of a room is decreased by 10% and breadth is decreased by 20%, while height is increased by 5%, then what is the percentage change in th
    Question

    If the length of a room is decreased by 10% and breadth is decreased by 20%, while height is increased by 5%, then what is the percentage change in the volume of the room?

    A.

    24%

    B.

    24.4%

    C.

    24.2%

    D.

    24.6%

    Correct option is B

    Given:
    Length change = –10%
    Breadth change = –20%
    Height change = +5%
    Formula used:
    % Change in Volume = (a+b+c)+ab+bc+ca100+abc10000 (a + b + c) + \frac{ab + bc + ca}{100} + \frac{abc}{10000}​​
    Solution:
    a+b+c=1020+5=25ab+bc+ca100=(10)(20)+(20)(5)+(10)(5)100=20010050100=50100=0.5abc10000=(10)(20)(5)10000=100010000=0.1a + b + c = -10 - 20 + 5 = -25 \\\frac{ab + bc + ca}{100} = \frac{(-10)(-20) + (-20)(5) + (-10)(5)}{100} = \frac{200 - 100 - 50}{100} = \frac{50}{100} = 0.5 \\\frac{abc}{10000} = \frac{(-10)(-20)(5)}{10000} = \frac{1000}{10000} = 0.1​​
    Total % change = -25 + 0.5 + 0.1 = -24.4%
    The correct answer is (b).

    Free Tests

    Free
    Must Attempt

    UPTET : Paper 1 Full Mock - 01

    languageIcon English
    • pdpQsnIcon150 Questions
    • pdpsheetsIcon150 Marks
    • timerIcon150 Mins
    languageIcon English
    Free
    Must Attempt

    UPTET : Paper 2 Maths & Science Full Mock - 01

    languageIcon English
    • pdpQsnIcon150 Questions
    • pdpsheetsIcon150 Marks
    • timerIcon150 Mins
    languageIcon English
    Free
    Must Attempt

    UPTET : Paper 2 Social Science Full Mock - 01

    languageIcon English
    • pdpQsnIcon150 Questions
    • pdpsheetsIcon150 Marks
    • timerIcon150 Mins
    languageIcon English
    test-prime-package

    Access ‘UPTET’ Mock Tests with

    • 60000+ Mocks and Previous Year Papers
    • Unlimited Re-Attempts
    • Personalised Report Card
    • 500% Refund on Final Selection
    • Largest Community
    students-icon
    446k+ students have already unlocked exclusive benefits with Test Prime!
    Our Plans
    Monthsup-arrow