If in a certain shipment of new cars, the cost of car X is twice the

Question

If in a certain shipment of new cars, the cost of car X is twice the average of the other 11 cars in the shipment, what fraction of the total cost of 12 cars is the cost of car X ?

(A) 1/12

(B) 1/11

(C) 2/13

(D) 2/11

(E) 1/6

pushpitkc · Answer

Let the average price of the 11 cars be p. 
Since, the cost of car X is twice the average, it must be 2p.

Therefore, Car X as a fraction of the total cost of 12 cars is  \frac{2p}{2p+11p} = \frac{2p}{13p} = \frac{2}{13}  (Option C)

generis · Answer

Another approach: Assign values

1) Assigned values
Let 11 cars' average cost = $1
Car X cost is twice that average: (2 * $1) = $2

2) Total Cost of 11 cars + Car X?
Total cost of 11 cars: 
A * n = Sum
($1 * 11) = $11 total for all 11 cars

Total Cost of all 12 cars = 
(TC of 11 cars) + (Cost of Car X)
Total Cost of 12 cars: $11 + $2 = $13

3) Car X as fraction of total cost?

Fraction:   \frac{CarXcost}{TotalCost12cars}=\frac{$2}{$13}=\frac{2}{13}

Answer C

ScottTargetTestPrep · Answer

We can let the average of the 11 cars = n, so the cost of car X is 2n, and thus the total cost of all the cars in the shipment is:

11n + 2n = 13n

Now we can determine what fraction X is of the 12 cars:

2n/13n = 2/13

Answer: C

krish76 · Answer

Avg of 11 = a cost of X = 2a total cost = 13a fraction = 2a/13a=2/13 Answer "C" Took 2 mins

MvArrow · Answer

I picked numbers!

Let's assume that all the other 11 cars cost 5€ each
X = 2x5 and the total cost of the other 11 cars would be 55, hence the total cost of the 12 cars will be 55+10 = 65

10/65 --> 2/13, answer choice C

bumpbot · Answer

Automated notice from GMAT Club BumpBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

If in a certain shipment of new cars, the cost of car X is twice the

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

If in a certain shipment of new cars, the cost of car X is twice the

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards