Q: There was a big sale on cat food at the pet store. 20 people bought cat food that day. The first 8 customers bought 3 cases each. The next four customers bought 2 cases each. The last 8 customers of the day only bought 1 case each. How many cases of cat food were sold?
A: The first 8 customers bought 8 * 3 = 24 cases. The next 4 customers bought 4 * 2 = 8 cases. The last 8 customers bought 8 * 1 = 8. In total 24 + 8 + 8 = 40 cases were sold. The answer is 40.

Q: Jack buys a squat rack for $2500. The barbell cost 1/10 as much. How much did he pay for everything?
A: The barbell cost 2500 / 10 = $250. So he paid 2500 + 250 = $2750 for everything. The answer is 2750.

Q: A bicycle shop owner adds 3 bikes to her stock every week. After 1 month, she had sold 18 bikes but still had 45 bikes in stock. How many bikes did she have originally?
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
There are approximately 4 weeks in a month. The shop owner added 3 bikes every week for 4 weeks for a total addition of 3 * 4 = 12 bikes. The shop owner now has the original number of bikes + 12 bikes. She sold 18 bikes within the same time frame. She now has a total of 45 bikes which is: the original number of bikes + 12 - 18 = 45 bikes. The original number of bikes = 45 - 12 + 18 = 51 bikes. The answer is 51.