its not understandable.. could u please explain wonder_gmat?i am getting 1/6
A = average of all 11 cars
X = 2A..... (given)
We have to find the total of all cars (including X) in order to find the fraction that contributes to X.
Total = X + 11A ..... (we can use 11A here in place of total cost of all cars besides X)
= 2A + 11A
Now, we have to find the fraction of the total cost
that is contributed to X.
Fraction = X / Total
= 2A / 13A
= 2/13 ..... (A's cancel out)