Question 859405
Their rates working together are additive.  Use the rates as units of FIELD per MINUTE.


{{{1/45+1/65=CombinedRate}}}
{{{1/(3*3*5)+1/(5*13)}}}
{{{(1/(3*3*5))(13/13)+(1/(5*13))((3*3)/(3*3))}}}
{{{(13+9)/(3*3*5*13)}}}
{{{22/(3*3*5*13)}}}
{{{highlight(22/585)}}} Fields Per Hour


Viewed as the reciprocal, this is nearly 27 hours for one field.