Question: I caught 4 fewer fish than the number in my tank and added them to my fish tank. If the tank has 20 fish right now, how many did I add?
Answer: Let's say the number of fish that was in the tank before was x. If you caught 4 fewer fish than the number that was there, then you caught x - 4. After adding x - 4 fish into the tank, the tank now had 20 fish, meaning the total number of fish in the tank is x + x - 4 = 20. 2x = 20 + 4. The total number of fish that was initially in the tank is 2x = 24. Initially, there were x = 24 / 2 fish in the tank. x = 12. If you caught 4 fewer fish than the number in my tank initially, you caught 12 - 4 = 8 fish. The answer is 8.

Question: Lily types 15 words a minute and takes a 2-minute break every 10 minutes. How long does it take for Lily to type 255 words?
Answer: It would take Lily 255 words / 15 wpm = 17 minutes to type without taking a break. Since Lily takes a break after 10 minutes of typing she takes 17 minutes + 2 minutes = 19 minutes. The answer is 19.

Question: Juan needs 10 half-gallons of milk to bake 40 cookies with. How many half-gallons of milk does Juan need to bake 200 dozen cookies?
Answer: If 10 half - gallons of milk bake 40 cookies, then one half - gallon of milk bakes 40 / 10 = 4 cookies. If one half - gallon of milk bakes 4 cookies. to bake 200 cookies, you'll need 200 / 4 = 50 half - gallons of milk. The answer is 50.

Question: Tony puts $1,000 in a savings account for 1 year. It earns 20% interest. He then takes out half the money to buy a new TV. The next year, the remaining money earns 15% interest. How much is now in the account?
Answer:
After one year he earns $200 in interest because 1,000 x .2 = 200. After one year it has $1,200 in the account because 1,000 + 200 = 1,200. He takes out $600 because 1,200 / 2 = 600. After this it has $600 in it because 1,200 - 600 = 600. She earns $90 in interest because 600 x .15 = 90. The account now has $690 because 600 + 90 = 690. The answer is 690.