1. Solution: Let the length be 3Xcm, the width be 2Xcm and the height be Xcm.

4(3X+2X+X)= 144

X=6

Answer: The length, width and height of this cuboid are 18cm, 12cm and 6cm respectively.

2. Solution: Suppose Beijing contributes X million yuan, Tianjin contributes Y million yuan and Shanghai contributes Z million yuan.

①:X+Y+Z= 1200

②:2X=Y+Z

③:3Y=X+Z

Solve with the above three formulas: X=400, Y=300, Z=500.

A: Shanghai invested 5 million yuan.

3. solution: let the length of the first root be x and the length of the second root be y.

X-2/5X = 4/7 years

X=20/2 1Y

Answer: The length of the first root is 20/2 1 of the second root.

4. Solution: There are X jeeps and Y tricycles.

①:X+Y= 12

②:4X+3Y=4 1

Solve with the above two formulas: X=5, Y=7.

A: There are five jeeps and seven tricycles.

5. No picture, no truth. . .

6. Solution: The number of people in Workshop A is 4X, and that in Workshop B is 3X.

3X-4( 1- 1/3)X=5

X= 15

4X=60

A: There are 60 people in Workshop A. ..

They are all standardized problem-solving formats, and they are all played by hand. I hope I can help you!