help with the following:

5. The following information is available for Bluewood Corporation for a sales volume of 500 stereo speakers for the past month: Total Per Unit Sales $225,000 $450 Less: variable expenses 80,000 160 Contribution margin $145,000 $290 Less: fixed expenses $ 35,000 Net operating income $110,000 What is the contribution margin ratio? a. 12.0% b. 30.0% C. 40.0% d. 64.4%6. The following information is available for Bluewood Corporation for a sales volume of 500 stereo speakers for the past month: Total Per Unit Sales $225,000 $450 Less: variable expenses 80,000 E Contribution margin $145,000 @ Less: xed expenses $ 35,000 Net operating income $110,000 If sales increase by $51,750, net income will increase by what amount? a. $ 6,000 b. $ 8,000 c. $20,000 d. $33,350