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)? Let's think first. Chain of thought:
User
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.
Therefore, the answer is 12.
Assistant