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The first volume of mathematics teaching and learning in seventh grade
Question 6: If the speed of car B is xkm/h, then the speed of car A is (2x+20) km/h. 。

1/2x+ 1/2(2x+20)= 298。

x= 192

2x+20=2 times 192+20=404.

Question 10:

Analysis: when they were separated by 36km for the first time, they walked in opposite directions and never met; The second time, 36 kilometers apart, they walked in the opposite direction and met.

Scheme 1: From 10 to 12, Wang Li and Chen Ping walked 36+36=72(km) in two hours, so from 8: 00 to 10, Wang Li and Chen Ping also walked 72km in two hours. Let the distance between a and b be xkm, then x

Solution 2: Let the distance between the two places be xkm, and at 10 in the morning, the distance traveled by the two people is (x-36)km. The speed sum is x-36/2 km/h, and when12 a.m., the distance traveled by the two people is (x+36)km, and the speed sum is X+36/4 km.

All right! o(∩_∩)o ..