After the July rainstorm hit Beijing, the country is actively involved in the relief work of a company donated a number of medical equipment must be 120 tons of supplies.

Err ...... actually a math problem ...... Well, do it

Let's say that there are x, y, and z cars in A, B, and C respectively, so we can make the following system of equations

5x+8y+10z=120

x+y+z=14

This is the first time that a company has donated 120 tons of medical equipment to a disaster relief effort.

x+y+z=14

This way the following conclusion can be deduced by elimination

y=5*(10-z)/3

x=2*(z-4)/3

Because x and y need to satisfy the condition of being positive integers at the same time. Thus

From conclusion 1, z can only be equal to 1, 4, 7

From conclusion 2, z can only be greater than 4

Combining the above conclusions, we arrive at Z=7, and so we deduce that X=2 and Y=5

So the number of models of A, B, and C is 2, 5, and 7

The total freight cost is 2×400+5×500+7× 600 = 7,500 yuan