Question: 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?
Answer: 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 is 2.

Question: Karen is planning writing assignments for her fifth grade class. She knows each short-answer question takes 3 minutes to answer, each paragraph takes 15 minutes to write, and each essay takes an hour to write. If Karen assigns 2 essays and 5 paragraphs, how many short-answer questions should she assign if she wants to assign 4 hours of homework total?
Answer: First figure out how many minutes 4 hours is: 4 hours * 60 minutes / hour = 240 minutes. Then figure out how long the two essays will take by multiplying the time per essay by the number of essays: 2 essays * 1 hour / essay * 60 minutes / hour = 120 minutes. Use the same method to find the total time spent writing paragraphs: 15 minutes / paragraph * 5 paragraphs = 75 minutes. Now subtract the time spent on essays and paragraphs from the total time to find the time spent on all the short answer questions: 240 minutes - 120 minutes - 75 minutes = 45 minutes. Finally, divide the total time spent on short - answer questions by the time per question to find the number of questions: 45 minutes / 3 minutes / question = 15 questions. The answer is 15.

Question: Anahi bought a 500 pages book to write some notes on. In the first week, she wrote on 150 pages. In the second week, she wrote on 30% of the remaining pages. While continuing writing, she accidentally spilled coffee on the book and damaged 20 percent of the empty pages she was to write on. Calculate the total number of empty pages available for her to write on now.
Answer: If she bought a 500 pages book and wrote on 150 pages, the number of empty pages remaining is 500 - 150 = 350 pages. She then wrote on 30% of the remaining empty pages on the second week, a total of 30 / 100 * 350 = 105 pages. The number of remaining empty pages is 350 - 105 = 245 pages. When she spilled coffee on the remaining empty pages, the number of damaged pages was 20 / 100 * 245 = 49. The number of empty pages remaining that she could write on is 245 - 49 = 196 pages. The answer is 196.

Question: One necklace is worth $34. Bob decided to buy one for his wife. But, he also bought a book, which is $5 more expensive than the necklace. Before he went shopping, Bob set a limit and decided not to spend more than $70. How many dollars over the "limit" did Bob spend?
Answer:
The book is $5 more expensive than the necklace, which means the book costs 34 + 5 = $39. Both products which Bob wants to buy cost in total 39 + 34 = $73. So Bob will spend 73 - 70 = $3 over the limit. The answer is 3.