James needs 40 fish to make one sushi roll. He goes to the market and buys 400 fish, but later finds out that 20% of the fish have gone bad and cannot be used. How many sushi rolls did James make with the remaining fish? Think carefully first, then make a decision:
If James bought 400 fish, the number of fish that were bad is 20 / 100 * 400 = 80. The remaining fish that he used to make the sushi rolls is 400 - 80 = 320. If 40 fish are required to make one sushi roll, 320 fish will make 320 / 40 = 8 sushi rolls. So, the answer is 8.