Step-by-step reasoning process: If you buy 18 units, the percentage of the total price drops to 100% - 20% = 80%. If 80% is equal to $500, then 100% is equals 100% / 80% * $500 = $625.
[Q & A] The question is You can lower the price by 20% if you buy more than fifteen units of iPhone cases. If you pay $500 to buy 18 units, what is the original price?
The answer is 625

Step-by-step reasoning process: The second day he visited 20 * 2 = 40 houses. So he sold things at 40 * .8 = 32 houses. So in total he sold things at 20 + 32 = 52 houses. That means he sold 52 * 2 = 104 things.
[Q & A] The question is James visits 20 houses to try and make a sale. He manages to sell something in every house. The next day he visits twice as many houses but only sold to 80% of houses. If he sold two things at each house in each of the two days, how many items did he sell?
The answer is 104

Step-by-step reasoning process: First find the number of cans of tomatoes in a normal batch of chili: 2 cans * 150% = 3 cans. Then add the number of cans of each type of food to find the total number of cans per batch: 3 cans + 2 cans + 1 can = 6 cans. Then multiply the number of cans per batch by the number of batches to find the total number of cans: 6 cans / batch * 4 batches = 24 cans.
[Q & A] The question is Carla adds a can of chilis, two cans of beans, and 50% more tomatoes than beans to a normal batch of chili. If she makes a quadruple batch, how many cans of food does she need?
The answer is 24

Step-by-step reasoning process: The second ring cost 2 * 10000 = $20,000. He sells the first ring for 10,000 / 2 = $5000. So he is out of pocket 10000 - 5000 = $5000. So that means he is out of pocket 20,000 + 5000 = $25,000.
[Q & A]
The question is Jim buys a wedding ring for $10,000. He gets his wife a ring that is twice that much and sells the first one for half its value. How much is he out of pocket?
The answer is 25000