Luis bought stock at $66.80. the next day, the price increased $13.85. this new price changed by −2 3 /4 % the following day. what was the final stock price, rounded to the nearest cent? ?

We know that
1) Luis bought stock at > $66.80
2) The next day, the price increased $13.85> $66.80+$13.85=$80.65
3) This new price changed by −2 3 /4 % the following day
2 3/4%> (2*4+3)/4> 11/4 %> 2.75%
so
(100%-2.75%)> 97.25%
the final stock price is $80.65*0.9725> $78.43

the answer is 
$78.43