"Average" with error DIV/0

Taking average from data below I get DIV/0 Error

J42=AVERAGE(J40:J41)

J40 00:16:40
J41 00:09:53
J42 #DIV/0!

Thank you

I suspect the entries in J40 and J41 are text entries, rather than
numeric. Test for this by entering the formula =ISNUMBER(j40) in an
open cell. If you get a FALSE response, then you can write a formula
=TIMEVALUE(J40) that will translate the text cell into a time.
Remember to format the TIMEVALUE cell with a time format.