Finding masses with moles question

I am wondering about 4C in specific. I tried working out the answer and for finding the moles of CuFeS2 i used the balanced equations in 4a. I used the 2nd equation in 4a to find the moles of Cu2O and then used that in the first equation to find CuFeS2 moles but that is clearly wrong and i don't get what they did in the mark scheme. I'd appreicate any help

the problem is you do not need to use the previous equations. So it becomes of 1:1 ratio of Cu: CuFeS2.