I$$m not sure why the assignment did not accept the $$43,241.$

What was written makes sense, and I follow that approach in Excel.

$=$NPV$($Rate$,$Investment,CF$1$:CF$5)=$ $$43,241$

I also tried this but it didn$$t like this answer either

$=$NPV$($Rate$,$CF$1$:CF$5)+$Investment $=$ $$47,565$

In both cases, I used the Investment of $-$$$127,435$

I$$m not sure what I am missing. I calculated the Payback Period with the same figures and the assignment accepted that answer which was $3.$ Any additional suggestions?