Reconstruct a question, answer pair from this explanation: Angie earned 80 and paid 42 for necessities, so she had 80 - 42 = $38 left. Angie had 18 left after paying taxes, so her share of the taxes was 38 - 18 = $20 this month.
Q:Angie is part of a household with shared expenses and contributes $42 a month for necessities. She has a salary of $80 per month. She also pays a share of the household taxes each month. At the end of this month, she had $18 left over. How much did she pay in taxes this month?
A:20