Rounding off percentages in Section B

Sir in Section B there was this question where it asked to find the Return on Sales What I'm about to type is the relevant information to finding the return on sales The information is as followed before Operating profit: $600,000 Sales Revenue : $3,600,000 Sir when I was calculating return on sales I did this method. =(600000/3600000)*100 I got the answer as a recurring figure Since we usually correct to 2d.p I used the figure the 16.68% However this is wrong and the correct answer is 17% Sir please explain me to what decimal I should correct to because i remember that I have asked a previous question in regard with correcting trade recievables days(my answer was a decimal answer and you said not to correct it unless the question specifies to round it to a certain decimal place) In this question for return on sales i couldn't write the whole answer because it was a recurring figure Sir please help me figure out how to deal with this type of question