Write a practical question about the journey according to the equation 20 / 3 + x = 15 / X

Write a practical question about the journey according to the equation 20 / 3 + x = 15 / X

The passenger car and freight car start from a place at the same time. The speed of the passenger car is 3 kilometers per hour faster than that of the train. It is known that when the passenger car runs 20 kilometers, the freight car only runs 15 kilometers
Let the speed of the freight car be X,
From the meaning of the title, 20 / (3 + x) = 15 / X
The solution is x = 9
The speed of the truck is 9 km / h

The equation | x + 1 | + | x + 99 | + | x + 2 | = 1992 has several solutions

Classification discussion:
(1)
When x ≥ - 1,
x+1+x+99+x+2=1992
3x=1890
x=630
(2)
-2≤x

How many solutions does the equation | x + 1 | + | x + 99 | + | x + 2 | = 1992 have?

2
630 and - 698

Finding the integer solution of equation (y + x) ^ 1949 + (Z + x) ^ 1999 + (x + y) ^ 2002 = 2

It must be y + X, x + Z, y + Z, where two are equal to 1 and the other is equal to 0
Concatenated equations or visual inspection
have to
0 0 1 or
0 1 0 or
1 0 0