You can probably use running totals, but I haven't, my solution is always shared variables.
if this calculation is for the whole report, we can skip the setting variables to 0.
you would create a couple of formulas. First goes in detail section and would look like:
shared numbervar Pass;
shared numbervar PassFail;
if {table.field}="Pass" then Pass := Pass + 1;
if {table.field}="Pass" OR {table.field}="Fail" then PassFail := PassFail +1;
"" //hide the calculations.
in the group footer/report footer
shared numbervar Pass;
shared numbervar PassFail;
Pass/PassFail
HTH