There are 320 ducks in a pond. On the first night 1/4 of them get eaten by a fox. On the second night 1/6 of the remaining ducks fly away, and on the third night 30 percent are stolen. How many ducks remain after the three nights?
Let's think: First night:320(1 / 4) = 80. 320 - 80 = 240. Second night:240(1 / 6) = 40. 240 - 40 = 200. Third night:200(.30) = 60. 200 - 60 = 140 ducks remain.. The answer is: 140.

A school is buying virus protection software to cover 50 devices. One software package costs $40 and covers up to 5 devices. The other software package costs $60 and covers up to 10 devices. How much money, in dollars, can the school save by buying the $60 software package instead of the $40 software package?
Let's think: There are 50 / 5 = 10 sets of 5 devices in the school. So the school will pay a total of $40 x 10 = $400 for the $40 software package. There are 50 / 10 = 5 sets of 10 devices in the school. So the school will pay a total of $60 x 5 = $300 for the $60 software package. Thus, the school can save $400 - $100 = $300 from buying the $60 software instead of the $40 software package.. The answer is: 100.

Bill milked his cow and got 16 gallons of milk. He turned 1/4 into sour cream, 1/4 into butter, and kept the rest as whole milk. It takes 4 gallons of milk to make one gallon of butter and 2 gallons of milk to make 1 gallon of sour cream. If Bill sells butter for $5/gallon, sour cream for $6/gallon, and whole milk for $3/gallon, how much money does he make?
Let's think: First find how much milk Bill turned into sour cream and butter: 16 gallons * 1 / 4 = 4 gallons. Then find how many gallons of butter he makes out of 4 gallons of milk: 4 gallons milk / 4 gallons milk / 1 gallon butter = 1 gallon butter. Then find how many gallons of sour cream he makes out of 4 gallons of milk: 4 gallons milk / 2 gallons milk / 1 gallon sour cream = 2 gallon sour cream. Then subtract the amount of milk turned into butter and sour cream to find the remaining amount of whole milk: 16 gallons - 4 gallons - 4 gallons = 8 gallons. Then multiply the number of gallons of milk by the price of milk to find the total cost of the milk: 8 gallons * $3 / gallon = $24. Then multiply the number of gallons of sour cream by the price of sour cream to find the total cost of the sour cream: 2 gallons * $6 / gallon = $12. Then add the cost of the butter, sour cream and milk to find the total amount of money Bill earns: $24 + $12 + $5 = $41.. The answer is: 41.

A couple's wedding reception had 180 people. The bride and groom had each invited 20 couples from their side of the family. The remaining guests were friends. How many friends attended the reception?
Let's think:
From the bride's side, 20 couples * 2 guests / couple = 40 guests attended. From the groom's side, 20 couples * 2 guests / couple = 40 guests attended. Therefore 180 guests - (40 guests + 40 guests) = 100 friends attended the reception.. The answer is: 100.