What is the Contribution Margin per hour of machine time for Test B

Needle Company Needle Company is a private laboratory that performs more than 100 different tests and analyses. Four tests require the use of a radiological counting machine that can supply 6,000 hours per year. Information on the four lab tests are as follows: Test A Test B Test C Test D Charging rate $50 $20 580 $70 Variable cost 10 10 60 30 Machine hours 2. 0.5 0.25 Refer to Needle Company. What is the contribution margin per hour of machine time for Test B? s10 Os20 O s40 $100