We can see in the table, on the top row, that the number of doghouses sold increases by 4 each column. When he sold 8 doghouses, he earned 40. When he sold 12 houses, he earned 60. This means that he earns $20 for every 4 doghouses sold.
If he earned $100 for selling 20 houses, if he sells 24 he will earn:
[tex]100+20=120[/tex]
Thus, the answer is option B. 120
