There are 66 goats at a farm and twice as many chickens. If the number of ducks is half of the total of the goats and chickens, and the number of pigs is a third of the number of ducks, how many more goats are there than pigs?
Let's think: There are 66 x 2 = 132 chickens. There are 66 + 132 = 198 goats and chickens. There are are 198 / 2 = 99 ducks. There are 99 / 3 = 33 pigs. There are 66 - 33 = 33 more goats than pigs.. The answer is: 33.

Last year, the school library purchased 50 new books. This year, it purchased 3 times as many books. If the library had 100 books before it purchased new books last year, how many books are in the library now?
Let's think: Last year, there were a total of 100 + 50 = 150 books in the library. The library purchased 50 x 3 = 150 books this year. Therefore, the library now has a total of 150 + 150 = 300 books.. The answer is: 300.

Alicia has to buy some books for the new school year. She buys 2 math books, 3 art books, and 6 science books, for a total of $30. If both the math and science books cost $3 each, what was the cost of each art book?
Let's think: The total cost of maths books is 2 * 3 = 6 dollars. The total cost of science books is 6 * 3 = 18 dollars. The total cost for maths and science books is 6 + 18 = 24 dollars. The cost for art books is 30 - 24 = 6 dollars. Since he bought 3 art books, the cost for each art book will be 6 / 3 = 2 dollars.. The answer is: 2.

Liza bought 10 kilograms of butter to make cookies. She used one-half of it for chocolate chip cookies, one-fifth of it for peanut butter cookies, and one-third of the remaining butter for sugar cookies. How many kilograms of butter are left after making those three kinds of cookies?
Let's think:
Liza used 10 / 2 = 5 kilograms of butter for the chocolate chip cookies. Then, she used 10 / 5 = 2 kilograms of butter for the peanut butter cookies. She used 5 + 2 = 7 kilograms of butter for the chocolate and peanut butter cookies. So, only 10 - 7 = 3 kilograms of butter was left. Then, Liza used 3 / 3 = 1 kilograms of butter for the sugar cookies. Therefore, only 3 - 1 = 2 kilograms of butter were left.. The answer is: 2.