why is this the answer?

River Corp sells pontoon boats. Data from the corporate budget for next year is: Sales $2,000,000 Fixed expenses $100,000 Variable expenses $1,800,000 If sales hold at $2,000,000, but there is a 15% increase in the contribution margin, net income is: Submit No. The answer is $130,000. The contribution margin increases from $200,000 to $230,000. $230,000 less $100,000 in fixed expenses is $130,000. Click next to continue