Given below are two quantities named A and B. Based on the given information, you have to determine the relationship between the two quantities. You should use the given data and your knowledge of Mathematics to choose between the possible answers.

Quantity A: The average marks of a class of 40 students are found to be 63. Later it was found that the marks of two students were written as 82 and 93 instead of 28 and 39. Find the correct average marks of the class. 

Quantity B: 61