There are 25 students in Class One, Grade Two. They go by boat. 1 There are only 4 people in one article and 3 people in the other article. How come the boat is just full and there are no empty seats?
Seats are limited to 4 persons and 4 articles: 4x4 = 16 persons.
Seats are limited to 3 people and 3 articles: 3x3 = 9 people.
16+9 = 25 people
The answer is that three people take four boats and three people take three boats, so there is no room.