As the % increases this means, the new student got it correct

Let original number of students who originally attempted be x

The number of students who got the correct answer = 0.813x

After the new student:

Number of students who got it correct = 0.813x + 1

Total number of students = x + 1

% correct = \frac{0.813x + 1}{x + 1} * 100 = 82.4

81.3x + 100 = 82.4x + 82.4

1.1x = 17.6

x = 16

x + 1 =17

Ans. 17

Thank you so much.

On a test, 81.3 %81.3% of students got a certain question correct on their first try. After another student attempted the question, the success rate was 82.4 %82.4%. If no additional students attempted the question, how many people attempted the question in total?

They are asking for the total number of students who attempted the question.

An additional step I can provide you that’s not already in this thread is:

x = number of students who answered correctly

t = total number

x/t = 81.3% or 81.3/100

x + 1 = one more student got it correct

t + 1 = one more student attempted it so the total must be added as well

x+1/t+1 = 82.4% or 82.4/100

Notice that we have 2 equations with 2 variables so we can solve for t.