8th Class Mathematics Sample Paper Mathematics Sample Paper - 3

  • question_answer A number is increased by 20% and then it is decreased by 20%. Find the net increase or decrease per cent.

    Answer:

    Let the number be 100
    Increase in the number = 20% of 100 =20                                                                                                                           
    So,       increased number = 100 + 20 = 120
    Decrease in the number = 20% of 120
                \[=\frac{20}{100}\times 120=24\]                                                                                                                                              
    So,  new number \[=\text{ }120\text{ }-\text{ }24\text{ }=\text{ }96\]
    Net  decrease \[=\text{ }100\text{ }-\text{ }96\text{ }=\text{ }4\]
    Hence,   net decrease per cent
    \[=\frac{4}{100}\times 100=4%\]


adversite


You need to login to perform this action.
You will be redirected in 3 sec spinner