Seeking the answer to a problem in junior high school mathematics really can't be done.

Solution: 1) according to the meaning of the question:

Because the number of vehicles carrying A and B citrus is X and Y respectively.

Therefore, the number of vehicles transporting C citrus is 20-x-y.

Because three kinds of citrus * * * A, B and C weigh100t, and three kinds of citrus trucks A, B and C weigh 6, 5 and 4 tons respectively,

So the equation is 6X+5Y+4*(20-X-Y)= 100.

Simplifying the equation can get 2X+Y=20, that is, the equation where x represents y is Y=20-2X.

2) Since the profits of three kinds of citrus in ABC are 12, 16 and 10 ton/100 yuan respectively,

Therefore, the profits of A, B and C are 6X* 12, 5Y* 16 and 4(20-X-Y) hundred yuan respectively.

The equation is 6x *12+5y *16+4 (20-x-y) */kloc-0 =140800/100 =1408.

Simplified equation 4X+5Y=76 (1)

Y=20-2X (2)

So the equation can be composed of (1) and (2), and (2) can be substituted for (1).

X= 4, that is, Y=20-8= 12.

Therefore, the vehicle arrangement of C citrus is 20-4- 12=4.

I hope the attached article can make people see it more clearly, and I hope you can learn something from it! )