Question

A number is first increased by 20persent and then decreased by 20percent . find the net increase or decrease per cent

Answer 1

Suppose the pis x.(you may take it 100 for ease of calculation)
after 20% increase, it will [tex]x(1+ \frac{20}{100} ) [/tex]
= $1.2x$
then 20% decrease will be $1.2x(1- \frac{20}{100} )$
=$1.2x$×.8
=.96x
Hence net decrease = $\frac{(x-.96x)}{x}$×100 = 4%