The city of Fredericton operates automobile parking facilities and is evaluating a proposal to erect and operate a structure for parking in the city's downtown area. 2 designs for a facility to be built have been identified (all values are in thousands of dollars):

                                     Design A    Design B

Cost of site                         $297       $122
Cost of building                   $2,339    $519
Annual fee collection             $830      $750
Annual maintenance cost       $410      $360
Service life30 years            30 years

Determine the incremental (A-B) benefit-cost ratio if annual interest rate is 10%