Q: Bob orders a dozen muffins a day for $0.75 each and sells them for $1.5 each. How much profit does he make a week?
A: He buys them for 12 * .75 = $9. He sells them for 12 * 1.5 = $18. So he makes 18 - 9 = $9 per day. That means he makes 9 * 7 = $63 per week. The answer is 63.

Q: Last week, Charles bought a t-shirt for $30, a backpack for $10, and a blue cap for $5. The store gave him a discount and, in total, he only spent $43. How much of a discount did they give him, in dollars?
A: The purchases he made totaled $30 + $10 + $5 = $45. He should pay $45, but he only paid $43, so $45 - $43 = $2 was the discount they gave him. The answer is 2.

Q: Jon makes 3/4's the salary that Karen makes. John makes $3000 per month. How long will it take him to make the same amount of money that Karen does in 3 months?
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.
user
Karen makes $3000 / (3 / 4) = $4000 per month. In three months, Karen would make a total of $4000 * 3 = $12000. To make the same amount of money John would need to work $12000 / $3000 = 4 months. The answer is 4.