1, used 1/3 for the first time and 3/5 for the second time, so used 4/ 15 for the second time, leaving 2/5, so the remaining coal 300 divided by 4 times 6 is 450 tons.

The number of two kinds of balls is almost the same, and the number of football is a multiple of 6, so the two kinds of balls sold cost 5000 yuan.

According to common sense, there are 52 students in the class (/kloc-the least common multiple of 0/3 and 4), so there are 20 girls.