Question: A pen and pencil have a total cost of $6. If the pen costs twice as much as the pencil, what is the cost of the pen?
Answer: Let x be the cost of the pencil. If the pen costs 2 times the cost of the pencil, then it costs 2x. Adding the cost of the pen and pencil we get 2x + x = 3x. Since the total cost is $6 then 3x = $6 therefore x = $6 / 3 = $2. One pen is equal to 2 * x which is 2 * $2 = $4. The answer is 4.
[Question]Lily goes to the supermarket. She has $60. She needs to buy 6 items: celery, cereal, bread, milk, potatoes, and coffee. She finds a stalk of celery for $5, cereal for 50% off $12, bread for $8, and milk for 10% off $10. She finds potatoes for $1 each and buys 6. How many dollars does she have left to spend on coffee?
[Answer]Lily spends $5 + $8 = $13 on celery and bread. Lily spends $12 * (50 / 100) = $6 on cereal. Lily gets 10% off the milk, so she pays 100% - 10% = 90% of its original price. Lily spends $10 * 90% = $9 on milk. She spends $1 * 6 = $6 on potatoes. Thus, she has $60 - $13 - $6 - $9 - $6 = $26 left over for coffee. The answer is 26.
Q: Tammy has 10 orange trees from which she can pick 12 oranges each day. Tammy sells 6-packs of oranges for $2. How much money will Tammy have earned after 3 weeks if she sells all her oranges?
A: Tammy picks 10 trees x 12 oranges / tree = 120 oranges per day. Tammy sells 120 oranges / day / 6 oranges / pack = 20 6 - packs of oranges a day. Tammy sells 20 packs / day x 7 days / week = 140 6 - packs a week. In 3 weeks Tammy sells 140 packs / week x 3 weeks = 420 6 - packs. Tammy makes 420 packs x $2 / pack = $840. The answer is 840.
Question: At a CD store, 40% of the CDs cost $10 each, and the rest cost $5 each. Prince bought half the CDs sold at $10 each, and all of the CDs sold at $5 each. If the total number of CDs was 200, how much money did Prince spend on buying the CDs?
Answer: The number of CDs selling at $10 each at the store is 40 / 100 * 200 = 80. This means the store sells 200 - 80 = 120 CDs at $5 each. Prince bought 1 / 2 * 80 = 40 of the CDs selling at $10 each. The total amount of money Prince paid for the 40 CDs selling at $10 each is $40 * 10 = $400. If he bought all the CDs selling at $5 each, he paid a total of $5 * 120 = $600. For all the CDs he bought, Prince spent $600 + $400 = $1000. The answer is 1000.
[Question]An iron bar measures 12 cm by 8 cm by 6 cm. A factory wants to melt ten iron bars and mold them into iron balls. Each iron ball has a volume of 8 cubic cm. How many iron balls have been molded?
[Answer]The volume of 1 iron bar is 12 cm x 8 cm x 6 cm = 576 cubic cm. The volume of 10 iron bars is 10 x 576 cubic cm = 5760 cubic cm. Therefore, there are 5760 / 8 = 720 iron balls that have been molded. The answer is 720.
[Question]In a restaurant, one cup of coffee is $6 and a piece of cheesecake $10. When buying them together, the client gets a 25% discount. What is the final price of such a set?
[Answer]

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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Both the cheesecake and coffee cost 10 + 6 = $16. The discount for these items is 25 / 100 * 16 = $4. So the final price for the cheesecake and coffee is 16 - 4 = $12. The answer is 12.