If we assume that the number of trucks on the highway is t, the number of cars on the highway will be 2*t = 2t
The total number of cars and trucks on the road is 2t+t= 300
The number of vehicles on the road is 3t=300
The are t=300/3 trucks on the highway.
This means there are t=<<100=100>>100 trucks on the road.
#### 100