Operating data from Tindall Company for last year follows:

Sales	$945,000
Stockholders equity	$515,000
Return on investment	21%
Average operating assets	?
Turnover	1.50
Residual income	?
Minimum required rate of return	18%
Total assets	$754,000

The average operating assets amounted to:

$754,000

$377,000

$515,000

$630,000