LSB Company has the following income statement:

Revenues $100,000

Variable costs 40,000

Contribution margin 60,000

Fixed costs 30,000

Operating Income 30,000

If LSB's sales increase by $20,000, what will be the company's operating profit?

a) $42,000

b) $12,000 <-------------------------- answer

c) $50,000

d) $30,000

The answer "b")12,000 is already given but I don't know how the answer key got that answer. Can someone explain to me where 12,000 operating profit came from?

I'm also a little confused because of of the wording.... is operating profit the same as operating income? please show your work and thanks in advance!