Q: Three old cars displayed in an auction event have different manufacture dates. The first car, made in 1970, was made 10 years earlier than the second car. The third car was manufactured 20 years later after the second car was manufactured. Calculate the year that the third car was made.
A: If the first car was made 10 years earlier than the second car, then the manufacture date for the second car is 1970 + 10 = 1980. The third car was manufactured 20 years after the second car was made, which is 1980 + 20 = 2000. The answer is 2000.
Question: Jenny signs up for dinner theater with 5 of her friends. Each person pays $50 for the ticket and $10 for their entrée, and half the people also buy unlimited drink tickets for $30/person. Then the dinner theater is canceled due to COVID, and each person gets a 90% refund. How much money did the group of six friends lose?
Answer: First find the cost of the ticket and the entrée for each person: $50 / person + $10 / person = $60 / person. Then multiply that cost by the number of people to find the total cost of entrees and tickets: $60 / person * 6 people = $360. Now find how many people ordered drink tickets: 6 people / 2 = 3 people. Now find the total cost of the drink tickets: 3 people * $30 / person = $90. Now find the total cost of the evening: $90 + $360 = $450. Now multiply this quantity by 90% to find the amount of the refund: $450 * .9 = $405. Now subtract the refund amount from the total cost to find how much money the friends lost: $450 - $405 = $45. The answer is 45.
[Question]Every day, while going to school, Shane drives a total of 10 miles. Calculate the total distance he drives in an 80 day semester from home to school and back.
[Answer]To go to school and back, Shane drives 2 * 10 = 20 miles per day. In 80 days of a semester, he drives for 80 * 20 = 1600 miles. The answer is 1600.
Q: Kendy made 2 online bank transactions. She transferred $60 to her mom and half that amount to her sister. As a result, her account now has $100 left in it. How much money was in the account before the transfer?
A: Kendy transferred $60 x 1 / 2 = $30 to her sister. So, She transferred a total of $60 + $30 = $90. Therefore, Kendy has $100 + $90 = $190 in the account before the transfer. The answer is 190.
Question: John decides to learn how to play the piano. He buys a piano for $500. He then hires a teacher for 20 lessons at $40 per lesson but ends up getting a 25% discount. How much did everything cost?
Answer: The normal price of the lessons would be 20 * 40 = $800. The discount saves him 800 * .25 = $200. So the lessons cost him 800 - 200 = $600. That means everything costs 500 + 600 = $1100. The answer is 1100.
Q: The price of a book was $400. If the book's price is decreased by 15% and then increased by 40%, what is the final price of the book?
A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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When the price of the book is decreased by 15%, the total price decrease is 15 / 100 * $400 = $60. The new price of the book becomes $400 - $60 = $340. The price of the book is then increased by 40 / 100 * 340 = $136. The final price of the book is $340 + $136 = $476. The answer is 476.