Original tv cost: 700$ current tv cost: 500$ find the percent of decrease round to the nearest whole percent

we know that

100%>  $700 (is the Original tv cost)
 X %>  $500 (is the Current tv cost)
x=500*100/700> 71.43%

the percent of decrease=100%-71.43%> 28.57%> 29%

the answer is
 the percent of decrease  is 29%