Question

Original tv cost: 700$

Answer 1

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%