Formula: 18/(5-3)=9 (person)
Male: 3*9=27 (person)
Female: 5*9=45 (person)
Analysis: The first step is to find out how many people there are in each copywriter. First of all, think about why there are 18 people missing. The reason is that there are two fewer boys than girls, so dividing the number of poor by the number of poor copies is the number of people in each copy, and then multiplying the number of boys and girls by the number of people in each copy to get the answer.
2.
Solution: There are x tons of coal in pile A and (72-x) tons of coal in pile B. 。
( 1-4/5)x = 1-3/4(72 x)
1/5x = 1/4(72-x)
4x = 5(72 times)
4x = 360-5x
9x = 360
x = 40
B: 72-40=32 (ton)
Analysis: first of all, we must grasp that the two are equal after shipment. We can make an equation based on this, and then let A be X, so that B has (72-x) tons. A shipped 4/5, so we subtract it from 1. Similarly, 3/4 of B is also subtracted by 1 to get the equation 1-4/.