Question: 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?
Solution:
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
Answer: 8