Answer:
A (30-(100/1000)x120)
Explanation:
I is a volume quantity, D is a distance quantity, and E is a rate measured as volume/distance.
So ExD gives us volume quantity.
Distance units are consistent (kilometers) but the volume units of E are inconsistent with those of I and the desired answer.
Let's convert E to liters per kilometer. We will use the fact that there are 1000 cubic centimeters per liter.
You get: 30 liter - 100/1000 liters/kilometer x 120 kilometers
In conclusion, this is the calculation that will give us the estimated volume of fuel that remains in Carson's tank by the end of the drive, in liters:
30-100/1000x120.
Hope this helps!