Answer the following question.
The news announced a $0.4 oil price rollback this Friday. Mr. Deane decided to only fill his gas tank with 10 liters of gas today and then another 25 liters on Friday. If the cost per liter of gas is $1.4 today, how much will Mr. Deane spend for his 35 liters of gas?
Step-by-step reasoning process: Mr. Deane will spend $1.4 / liter x 10 liters = $14 for the 10 liters of gas today. The price of the gas per liter on Friday will be $1.4 / liter - $0.4 / liter = $1 / liter. So, he will spend $1 / liter x 25 liters = $25 for the 25 liters of gas on Friday. Thus, Mr. Deane will spend a total of $14 + $25 = $39 for the 35 liters of gas.
The answer is 39.

Answer the following question.
Anna is reading a 31-chapter textbook, but she skips all the chapters that are divisible by 3. If it takes her 20 minutes to read each chapter, how many hours does she spend reading total?
Step-by-step reasoning process: First divide 32 by 3, ignoring the remainder, to find how many chapters in the book are divisible by 3: 31 / 3 = 10.33..., which means 10 chapters are divisible by 3. Then subtract that number from the total number of chapters to find how many chapters she reads: 31 chapters - 10 chapters = 21 chapters. Then multiply the number chapters by the time to read each chapter to find the total time she spends reading: 21 chapters * 20 minutes / chapter = 420 minutes. Then divide that time by the number of minutes per movie to find the total time spent reading in hours: 420 minutes / 60 minutes / hour = 7 hours.
The answer is 7.

Answer the following question.
Ivan had $10 and spent 1/5 of it on cupcakes. He then spent some money on a milkshake and had only $3 left. How much is the milkshake?
Step-by-step reasoning process: Ivan spent a total of $10 - $3 = $7 on cupcakes and a milkshake. The cost of the cupcake is $10 x 1 / 5 = $2. So, $7 - $2 = $5 was spent on the milkshake.
The answer is 5.

Answer the following question.
Three years ago, Rosie purchased an art piece for $4000. The same art piece will be three times as much in another three years. How much money will the art piece have increased by?
Step-by-step reasoning process: If the art piece was bought at $4000, and its price in three years will be three times its buying price, it will be worth 3 * $4000 = $12000 in another three years. The price of the art piece will increase by $12000 - $4000 = $8000.
The answer is 8000.