There are a total of 11 + 1 = <<11+1=12>>12 boys in the class.

Hence, there are a total of 12 boys + 13 girls = <<12+13=25>>25 students in a class.

So 13/25 x 100% = 52% of the class are girls.

# Answer

52
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
There are 11 boys and 13 girls in a class. If 1 boy is added to the class, what percentage of the class are girls?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
52
There are 11 boys and 13 girls in a class. If 1 boy is added to the class, what percentage of the class are girls?
train