Traci and Harris are baking cakes together. Traci has brought flour from her own house and Harris has 400g of flour in his house. Each cake needs 100g of flour and Traci and Harris have created 9 cakes each. How much flour, in grams, did Traci bring from her own house? Give the rationale and then the answer.
Let's think step by step. To make the cakes, Traci and Harris used a total of 9 cakes * 100g of flour per cake = 900g of flour. Traci therefore brought 900g of needed flour – 400g of flour from Harris’ flour = 500g of flour from her own house.. The answer is: 500.

Isabela bought twice as many cucumbers as pencils, with both costing $20 each. If she got a 20% discount on the pencils and bought 100 cucumbers, calculate the total amount she spent to buy the items. Give the rationale and then the answer.
Let's think step by step. Isabela bought twice as many cucumbers as pencils, meaning she bought 100 / 2 = 50 pencils. The total cost for purchasing the pencils without the discount is 50 * $20 = $1000. At a 20% discount, Isabela paid 20 / 100 * $1000 = $200 less. The total amount of money she used to buy the pencils is $1000 - $200 = $800. She also bought the cucumbers at a total cost of $20 * 100 = $2000. The total cost for the items is $2000 + $800 = $2800.. The answer is: 2800.

A bookseller sells 15 books in January, 16 in February and a certain number of books in March. If the average number of books he sold per month across all three months is 16, how many books did he sell in March? Give the rationale and then the answer.
Let's think step by step. He sold an average of 16 books per month across all 3 months so he must have sold a total of 3 * 16 = 48 books in those 3 months. He sold 15 + 16 = 31 in January and February. He must have sold 48 - 31 = 17 books in March.. The answer is: 17.