Don't know what i did wrong

OK, so this is a practice GRE question with no solution just the answer and I don't understand it. "A survey asked 1150 people to choose their favorite detergent from brands A, B, C. Of the people surveyed X percent chose A. If X is rounded to the nearest integer, the result is 3. Which of the following could be the number of people who chose A as their favorite brand? Indicate all such numbers. 20, 25, 30, 35, 40, 45, 50" I chose 20, 25, 30, based off of 3% of 1150 is 34.5. But appearantly the answer is 30, 35, 40. Someone please explain this!!