[Question]Susan had a sum of money. She spent 1/5 of it in September, 1/4 of it in October, and $120 in November. After spending these amounts of money, she still had $540 left. How much money did she have at first?
[Answer]Let X be the amount Susan had originally. Susan spent 1 / 5 * X in September, 1 / 4 * X in October, and $120 in November. Susan has X - 1 / 5 * X - 1 / 4 * X - $120 = $540 left. Combining like terms, we get 11 / 20 * X - $120 = $540. Adding $120 to both sides, we get 11 / 20 * X = $660. Dividing both sides by 11 / 20 we get X = $1200. The answer is 1200.
Q: The length of the straight part of a river is three times shorter than the crooked part. If the river is 80 miles long, how long is the straight part of the river?
A: Let's say the river's length in the straight part of the river is x. The total length of the river is the length of the straight part plus 3 times the length of the straight part for the crooked part, which is x + 3x = 80. The total length of the river is 4x = 80. The straight part of the river is x = 80 / 4 = 20 miles. The answer is 20.
Question: Bert bought some unique stamps for his collection. Before the purchase, he had only half the stamps he bought. If he bought 300 stamps, how many stamps does Bert have in total after the purchase?
Answer: Before the purchase, Bert had 300 * 1 / 2 = 150 stamps. So after the purchase he has 300 + 150 = 450 stamps. The answer is 450.
[Question]There were 21 dollars in the cookie jar. Doris spent $6 from the cookie jar. Martha spent half as much as Doris. How much money, in dollars, was left in the cookie jar?
[Answer]Martha spent 6 / 2 = 3 dollars. Martha and Doris spent 6 + 3 = 9 dollars. There were 21 - 9 = 12 dollars left in the cookie jar. The answer is 12.
Q: Romeo buys five bars of chocolate at $5 each and sells these chocolates for a total of $90. If he uses packaging material that costs him $2 for each bar of chocolate, how much profit does he make for all the chocolates he sells?
A: The selling price for each bar of chocolate is 90 / 5 = $18. The profit for each bar of chocolate is 18 - 5 - 2 = $11. The total profit is 11 * 5 = $55. The answer is 55.
Question: Darius has 5 buckets of water. One contains 11 ounces, one contains 13 ounces, one contains 12 ounces, one contains 16 ounces, and one contains 10 ounces. He pours the ten-ounce bucket into a bigger bucket, along with one of the other four. The total in the bigger bucket is now 23 ounces. He pours the remaining three buckets into a second large bucket. How many ounces does the second large bucket contain?
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.
user
Darius poured the 13 - ounce bucket into the first large bucket because 23 - 10 = 13. The remaining buckets are thus the 11, 12, and 16 ounce buckets. The second large bucket contains 39 ounces because 11 + 12 + 16 = 39. The answer is 39.