On Friday, Markeesha sold 30 boxes of crackers for her scout troop's fundraiser. On Saturday, she sold twice as many as on Friday. On Sunday, she sold 15 fewer than Saturday. How many boxes did she sell over the three days? Give the rationale and then the answer.
Let's think step by step. On Saturday, she sold 2 * 30 = 60 boxes. On Sunday, she sold 60 - 15 = 45 boxes. She sold a total of 30 + 60 + 45 = 135.. The answer is: 135.

There are 3 workers producing chairs in a furniture factory. Each of them produces 4 chairs an hour. As a group, they produce an additional chair every 6 hours. In total, how many chairs have been produced after 6 hours? Give the rationale and then the answer.
Let's think step by step. The workers produce a combined total of 3 workers * 4 hours = 12 chairs every hour. After 6 hours, they have therefore produced 12 * 6 = 72 chairs. Adding the additional chair means the total amount of chairs produced is 72 + 1 = 73 chairs.. The answer is: 73.

Selena reads a book with 400 pages. Harry reads a book with 20 fewer than half the number of pages Selena's book has. How many pages are in the book of Harry? Give the rationale and then the answer.
Let's think step by step. Half the number of pages of Selena is 400 / 2 = 200. Therefore, Harry's book has 200 - 20 = 180 pages.. The answer is: 180.