Q: A convenience store sold 100 bags of chips in a month. In the first week, 15 bags of chips were sold. In the second week, thrice as many bags of chips were sold. There was an equal number of chips sold in the third and fourth week. How many chips was each sold in the third and fourth week?
A: In the second week, 15 x 3 = 45 bags of chips were sold. So there was a total of 45 + 15 = 60 bags of chips sold on the first and second week. Thus, a total of 100 - 60 = 40 bags of chips were sold on the third and fourth week. Therefore, 40 / 2 = 20 bags of chips were each sold on the third and fourth week. The answer is 20.

Q: An amoeba reproduces by fission, splitting itself into two separate amoebae. An amoeba reproduces every two days. How many days will it take one amoeba to divide into 16 amoebae?
A: The amoeba will divide into 1 * 2 = 2 amoebae after 2 days. The amoeba will divide into 2 * 2 = 4 amoebae after 4 days. The amoeba will divide into 4 * 2 = 8 amoebae after 6 days. The amoeba will divide into 8 * 2 = 16 amoebae after 8 days. The answer is 8.

Q: Josh went to the shopping center. He bought 9 films and 4 books. He also bought 6 CDs. Each film cost $5, each book cost $4 and each CD cost $3. How much did Josh spend in all?
A:
The cost of the films is 9 × $5 = $45. The cost of the books is 4 × $4 = $16. The cost of the CDs is 6 × $3 = $18. Josh spent $45 + $16 + $18 = $79 in total. The answer is 79.