Deepthi Subbu wrote:If the mileage on car X is currently exactly 3 times the mileage on car Y, what is the mileage on car X?

(1) When each car had 6,000 miles less than they have now, car X had 4.5 times the mileage that car Y had.
(2) When each car has 2,000 miles more than they have now, car X will have 2.75 times the mileage that car Y will have.

Say, mileage of car X is x miles and that of car Y is y.
Thus, x = 3y

Statement 1: When each car had 6,000 miles less than they have now, car X had 4.5 times the mileage that car Y had. Thus, (x - 6000) = (4.5)*(y - 6000)
As we have two equations in two unknowns, we can solve for x.

Sufficient

Statement 2: When each car has 2,000 miles more than they have now, car X will have 2.75 times the mileage that car Y will have. Thus, (x + 2000) = (2.75)*(y + 2000)
As we have two equations in two unknowns, we can solve for x.

Sufficient

The correct answer is D.