blank cells

[datadude1959]

I need to calculate times that someone arrived somewhere and what time they had a test done. So far, I have figured these functions out, however, I have arrival time in say A2, testing time in A4, with the calculated time showing up in A8. If either A2 or A4 is blank, I need N/A to show up in A8????

Thanks

[flydecoder]

Try this
=if(or(A2="",A4=""),"N/A",<your existing formula>)

[datadude1959]

Sorry it took so long to say, Thank You.