Always read the question very carefully as it contains a lot of vital information's. Based on those information's the answer to the question can be easily deduced.
Total number of questions given in a Chinese test = 40
Percentage of questions incorrectly answered by Kara = 10%
Then
Number of questions incorrectly answered by Kara = (10/100) * 40
= 4
Then
The total number of questions correctly answered by Kara = 40 - 4
= 36
From the above deduction we can clearly see that Kara answered 36 questions correctly among the total of 40 Chinese questions that were given.