The managing director of a consulting group has the following monthly data on total overhead costs and professional labor hours to bill to clients

Overhead Costs $($$$)$

Billable Hours $($hrs$)$

$355,000$

$3,000$

$425,000$

$4,000$

$477,000$

$5,000$

$560,000$

$6,000$

$580,00$

$8,000$