Due to a drought, Jerry's household can only use 1000 gallons of water during July. Jerry uses 100 gallons for drinking and cooking and 20 gallons per shower. He wants to fill his pool, which measures 10 feet by 10 feet by 6 feet. If each gallon of water fills 1 cubic foot of the pool, how many showers can Jerry take in July? Think carefully first, then make a decision:
First find the total volume of the pool: 10 feet * 10 feet * 6 feet = 600 cubic feet. This is also the number of gallons he needs to fill the pool. Subtract the pool water and the drinking and cooking water from the total amount of water Jerry is allowed to use: 1000 gallons - 600 gallons - 100 gallons = 300 gallons. Then divide the amount of water Jerry has left to use for showers by the amount of water per shower to find how many showers he can take: 300 gallons / 20 gallons / shower = 15 showers. So, the answer is 15.