Answer:
The answer to the question is
If Boston is at D and C is 90 km away from Boston, then the two cars will meet at 30 km from Boston.
Step-by-step explanation:
Let the speed of the car that start from C = V₁
Let the speed of the car that start from D = V₂
Therefore where V₁ = 2·V₂
We have at time t when the cars meet the distance covered by the car that start from C will be V₁×t = 2·V₂×t, while the distance of the other car will be
V₂×t
Which means that the distance covered by the car that start from C is twice that of the car that start from D
Hence if Boston is located at D which is 90 km from C then both cars will meet at
90 km /3 = 30 km from Boston as the car originating from Boston would only have covered 30 km when the two cars meet.