Answer:
Weight of Train A = 454 tons
Weight of Train B = 35 tons
Step-by-step explanation:
It is given that:
Let,
A represent weight of Train A
B represent weight of Train B
According to given information:
A + B = 489 Eqn 1
A - B = 419 Eqn 2
Adding Eqn 1 and 2
A + B + A - B = 489 + 419
2A = 908
Dividing both sides by 2

Putting A = 454 in Eqn 1
454 + B = 489
B = 489 - 454
B = 35
Therefore,
Weight of Train A = 454 tons
Weight of Train B = 35 tons
Your proportion should look something like this

After cross multiplication, you should end up with this equation

After dividing 4 on both sides, you should get that x=9
Answer:
C.5.7
Step-by-step explanation:
plug in the x value then add 4.5 to 1.2 and booyyah