1. solution: let the total amount of plasticine be x, then the plasticine for each car body is x\20, and the plasticine for each wheel is x\ 120. The serial number of the whole vehicle model that this plasticine can make is: X \ (X \ 20+X \120× 4) = X \ (X \ 20+X \ 30) = X \ (5 \ 60x) =12.

2. Solution: 4x-3x=6-4

x=2

3. Solution: 8x-7x=4+3

x=7

4. Solution: Suppose she did the X problem correctly.

8x-5( 10-x)=4 1

8x-50+5x=4 1

13x=9 1

x=7

5. Solution: Workshop A has 7x employees and Workshop B has 3x employees. ..

(7x-30):(3x+30)=3:2

2(7x 30)= 3(3x+30)

14x-60=9x+90

14x-9x=90+60

5x= 150

x=30

Therefore, there are 30×70=2 10 people in Workshop A and 30×30=90 people in Workshop B. ..