Musa is the class teacher of a class of 45 students. He wants to split them into three groups by age. If a third of the class is under 11 years, and two-fifths are above 11 but under 13, how many students will be in the third group (13 years and above)? Give the rationale and then the answer.
Let's think step by step. The first group is a third of the class which is (1 / 3) * 45 = 15 students. There are 15 students in the first group, so there are 45 - 15 = 30 students. The second group is two - fifths of the class which is (2 / 5) * 45 = 18 students. There are 18 in the second group so there are 30 - 18 = 12 students left in the third group.. The answer is: 12.

DeShaun always wins the award in English class for reading the most books over the summer. This year is no different. Summer break is 80 days long. When he arrives, he notifies the teacher that he read 60 books over the summer. Each book averaged 320 pages long. The person closest to him read 75% as much as he did. How many pages did the second person read on average each day of break? Give the rationale and then the answer.
Let's think step by step. Deshaun read 19,200 pages because 60 x 320 = 19,200. The person closest to him read 14, 400 pages because 19,200 x .75 = 14,400. They read 180 pages a day because 14, 400 / 80 = 180.. The answer is: 180.

On Black Friday a popular electronics store sells 327 televisions. This is 50 more than they sold last Black Friday. If this sales trend continues and they sell 50 more televisions each year for three years, how many televisions will they sell on Black Friday three years from now? Give the rationale and then the answer.
Let's think step by step. The electronics store sold 327 televisions this Black Friday and might sell 50 more televisions the next year, for a total of 327 + 50 = 377 televisions. The second year they might sell 377 + 50 = 427 televisions. The third year, if they continue to sell 50 more televisions than they did the previous year, they will sell 427 + 50 televisions = 477 televisions on the Black Friday three years from now.. The answer is: 477.