Answer to the ninth question in the standard volume of Chinese unit 2 in grade 4 of Huanggang Junior Champion

Answer to the ninth question in the standard volume of Chinese unit 2 in grade 4 of Huanggang Junior Champion

"I don't want to think about whether I can succeed or not. Since I have chosen to go far away, I only care about wind and rain."

1. The distance between a and B is 446 km. The fast train runs 68 km per hour, the slow train 35 km per hour, and the slow train stops for half an hour. How many hours has it taken from the two trains to meet each other?
The two trains run from 470 kilometers away from each other. Car a runs 38 kilometers per hour, and car B runs 40 kilometers per hour. Car B goes out two hours before car a starts. How many hours later does bank a meet car B?

1. Let X be the same
68x+35(x-0.5)=446
x=4.5
Let's meet in X hours
（40+38）X=470-40×2
X = 5 hours

Please write down the meaning of each step
There are 42 fewer pear trees than apple trees in the orchard, and apple trees are three times as many as pear trees. How many apple trees and pear trees are there in the orchard?

42/(3-1)=21
42 trees is equivalent to twice of the increase, and that one should be 21
Pear 21 Apple 63