Two cars are running from two places 400 kilometers apart at the same time. Three hours later, they are 10 kilometers apart. It is known that one car runs 55 kilometers per hour. How can we find the speed of the other car? (answer in two ways)

Two cars are running from two places 400 kilometers apart at the same time. Three hours later, they are 10 kilometers apart. It is known that one car runs 55 kilometers per hour. How can we find the speed of the other car? (answer in two ways)

Use the arithmetic method: (400-10) △ 3-55, = 390 △ 3-55, = 130-55, = 75 (km / h); use the equation to set the speed of another car as X km / h, (55 + x) × 3 = 400-10, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 55 + x = 390 △ 3, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 55 + x = 130, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 130-55, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; &A: the speed of the other car is 75 kilometers per hour

The distance between the two places is 400 km. The two cars of a and Ji run towards each other from the two places at the same time. Car a runs 45 km per hour, and car a runs 55 km per hour. A few hours later, the two cars are 40 km apart

After X hours, the distance between the two vehicles is 40 km
（45＋55）X＋40＝400
100X＝360
X＝3.6