Bonus Calculation with multiple targets

Hello, 

I am trying to determine how I can calculate the amount of a bonus. In my example employees can get different bonus amounts based on how much they sell. There are 3 thresholds and corresponding bonus amount. 

40-55 apps    $25 per app >=40 and <=55

56-69 apps     $35mper app >=56 and <=69

70+                 $50 per apps >=70

I am looking for a formula that will calculate how many apps fall within each threshold. For example if someone has 57 apps how many 40-55 and how many 56-69? The payout would be 16 apps @ $25 each and 2 apps @ $35 each. Total bonus would be $470

Is there a formula that can do this? 

Thank you for your help!