Gail has some bills in her wallet which amount to $100. She has four $5 bills and three $20 bills, and the rest are $10 bills. How many $10 bills are in her wallet? Let's be accurate as possible.
Four $5 bills amount to $5 x 4 = $20. Three $20 bills amount to $20 x 3 = $60. So Gail's $5 and $20 bills amount to $20 + $60 = $80. Thus, her $10 bills amount to $100 - $80 = $20. Therefore, she has $20 / $10 = 2 $10 bills.
The answer: 2.