Calculating Average Of Two Ints And Converting To Double In Java?

how to use Java and for my coursework I have been asked to construct an application that will read in the exam mark and coursework mark and then print out to 1 decimal place the average of the coursework and exam mark. When I submit it to the coursework submission system it says it's incorrect.

The answer that it's asking for is the answer that my code produces (ex = 71 cw = 40 mark = 55.5) But for some reason it says this when I submit it:

-#### << Differences between expected (<) your answer (>) >> ------------
1c1
< ex= 91 cw = 80 mark = 85.5
---
> ex = 71 cw = 40 mark = 55.5
-------------------------------------------------------------------------

Check the above output for why this attempt failed And when I change the ex to 91 and cw to 80 it asks for > ex = 71 cw = 40 mark = 55.5 again.

class Main
{
public static void main( String args[] ) {
int ExamMark=71;
int CourseworkMark=40; 
double cost = (double)(ExamMark + CourseworkMark) / 2;
  System.out.printf("ex = " + ExamMark + " cw = " + CourseworkMark + " mark = " + cost);
System.out.println();
  }
 }