Ashley and Cassandra drove their cars along the same route for 400 mil

Question

Ashley and Cassandra drove their cars along the same route for 400 miles and then stopped at a gasoline station, where each purchased exactly the amount of gasoline needed to fill her car's gasoline tank to capacity. If both cars began with full gasoline tanks, which person's car consumed more gasoline during the 400-mile trip?

(1) At the gasoline station, Ashley purchased 10% less gasoline by volume than Cassandra purchased.

(2) The capacity of Ashley's gasoline tank is 15% less than the capacity of Cassandra's gasoline tank.

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Official Answer

A

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MartyMurray · Accepted Answer

Ashley and Cassandra drove their cars along the same route for 400 miles and then stopped at a gasoline station, where each purchased exactly the amount of gasoline needed to fill her car's gasoline tank to capacity. If both cars began with full gasoline tanks, which person's car consumed more gasoline during the 400-mile trip?

Statement (1)

(1) At the gasoline station, Ashley purchased 10% less gasoline by volume than Cassandra purchased.

We see that both cars began with full tanks. So, the amount of gasoline used by each car must be the same amount needed to fill that car's tank "to capacity" again.

Thus, since, if Ashley purchased less gasoline than Cassandra purchased, Cassandra needed more gasoline to fill her tank, Cassandra must have used more gasoline.

Sufficient.

Statement 2

(2) The capacity of Ashley's gasoline tank is 15% less than the capacity of Cassandra's gasoline tank.

Alone, this information on the relative capacities of the two tanks does not tell us anything about how much gasoline Ashley and Cassandra's cars consumed. After all, a car can consume a larger or smaller amount of fuel per mile regardless of the size of its tank.

Insufficient.

This question is written, with the wording "to capacity" in the question and "capacity" in statement (2), to tempt us to believe that the information on the capacities of the tanks provided by statement (2) is necessary for answering the question and that therefore the correct answer is (C).

However, the truth is that the information on the amount of fuel they purchased provided by statement (1) is sufficient.

Correct Answer   A

Key takeaway:

The GMAT uses matching wording to create traps to determine whether we understand what's going on in the question or are just going by vibe when choosing an answer.

Sonia2023 · Answer

chetan2u 
 Bunuel 
 KarishmaB

Are we assuming that consumption per mile (mileage) is same for both the cars? Otherwise sometimes I get no and sometimes yes:

chetan2u · Answer

The second row is not consumption but left over. 
Consumption is what is being filled.

So first case:
Capacity: 50 and 50
Filled: 10 and 11
Consumed: 10 and 11

Second case:
Capacity: 50 and 100
Filled: 10 and 11
Consumed: 10 and 11

The capacity does not come into play.

KarishmaB · Answer

The cars start at full capacity i.e. their tanks are full when they start their journey. 
Assume Ashley's car consumes x litres of gasoline during the journey and Cassandra's car consumes y litres during the journey. (The amount consumed will vary depending on their cars, their driving styles etc.)
At the end of the trip, they fill their tanks to capacity again. So basically, Ashley purchased x litres of gasoline and Cassandra purchased y litres of gasoline.

Question: Is x greater or is y greater?

(1) At the gasoline station, Ashley purchased 10% less gasoline by volume than Cassandra purchased. 
 
This tells us that x < y (Ashley purchased less than Cassandra). 
So we directly have the answer. This statement alone is sufficient.

(2) The capacity of Ashley's gasoline tank is 15% less than the capacity of Cassandra's gasoline tank. 
 
This tells us that Ashley's car has a smaller tank than Cassandra's. Does the size of the tank matter? Our concern is only the amount of fuel used and then re-purchased i.e. x and y only. The actual capacity of the tanks is irrelevant. This statement alone is not sufficient.

Answer (A)

jurgenklopp · Answer

Its given that both cars began with full gasoline tanks and in statement 2 ashley car fuel tank capacity is 15 percent less so doesnt it means that she will use less fuel to travel 400km ?

Bunuel · Answer

No, it doesn't necessarily mean that Ashley will use less fuel to travel 400 miles. The fuel consumption does not depend on the tank capacity; it depends on the fuel efficiency of the car. A smaller tank doesn't automatically mean less fuel used; Ashley's car could have used more fuel per mile than Cassandra's. Consider this: two tourists go for a hike. One takes 10 sandwiches, and the other takes 20. At the end of the hike, is it necessary that the tourist initially having fewer sandwiches ate less?

SergejK · Answer

Bunuel : but why is this considered to be in the hardest category? Pretty straightforward, right? Both cars were filled until capacity. S1 says that one bought more gas than the other but both filled up until capacity again, hence the first used more gas than the second. I mean I got it also wrong but only due to inattentiveness. Is there a trap I am not seeing? S2 is also straightforward: we don't know how much gas was bought. So where is the trap?

Bunuel · Answer

I believe this is due to the wording of the question. I agree that it’s a relatively simple question wrapped in a long stem and complex language. The key is to deduce that, since they both started with full tanks and are refilling them to capacity, the amount purchased directly reflects the amount consumed during the trip. Therefore, (1) clearly implies that Ashley consumed 10% less than Cassandra, making (1) sufficient. As for (2), it should be obvious that the capacity of a tank doesn’t determine the consumption rate, making (2) insufficient on its own.

mbaprepavi · Answer

The key point is that the amount of gasoline consumed is not determined by the size of the tank but by the fuel efficiency of the car.
The  capacity  of the gasoline tank simply  tells us  how much  fuel a car can hold , but  fuel consumption   depends  on how much  gasoline the car uses over a given distance , which is determined by the car’s  fuel efficiency

Since Statement (1) compares the amount of gasoline purchased (which corresponds to the amount consumed) and gives us that Ashley purchased 10% less than Cassandra, we don’t need to worry about the capacities of their tanks. The problem doesn't require us to know how large the tanks are; the amount of gasoline purchased tells us everything we need to know about the fuel consumption

Also, it might just be me but shouldn't the statement have been :  fill their tank  back  to full capacity 
Its not quite evident that " fill her car's gasoline tank to capacity " means filling from 0 to 100 (empty to full)

Anyways, trick question
Ans : A

SundayRoast · Answer

The Q does not state the gas tanks are the same size. If Ashley had a 100L tank and Cassandra had a 50L tank and say 50% was used then by Cassandra (i.e. 25L) then Ashley only needing to fill 45% would have to fill 45L so has used more gas.

DonBosco7 · Answer

Hi  sriharimurthy , Could you please explain this question with a Table method as it is described  here , Thanks !

MrMaxMan · Answer

They both started at full tanks.
They both drove the same distance.

I) After the same drive, ashley needed 10% less gas to fill her tank.
This means that to go the same distance she used less gas.
SUFF.

II) After the same drive, we learn that Ashley's tank is 15% smaller than Cassandra's.
This doesn't tell us anything about how much either she had to fill.
N.S.

FrozenDragon · Answer

Question : If both cars began with full gasoline tanks, which person's car consumed more gasoline during the 400-mile trip?

Person 
 Fuel Purchased  
 Tank Capacity 
 
  Ashley 
 A 
 ? 
 
  Cassandra 
 C 
 ?

Statement 1:

Ashley purchased 10% less fuel.
   Person 
 Fuel Used 
 
  Ashley 
 0.9C 
 
  Cassandra 
 C

Ashley used less fuel, so Cassandra used more.  Sufficient

Statement 2 :

Ashley's tank capacity is 15% less.

Person 
 Tank Capacity 
 Fuel Used 
 
  Ashley 
 0.85C 
 ? 
 
  Cassandra 
 C 
 ?

Tank size alone doesn't determine fuel used.  Not sufficient

Answer:  A

Ashley and Cassandra drove their cars along the same route for 400 mil

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Ashley and Cassandra drove their cars along the same route for 400 mil

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