Larissa and Steve each drove the same distance from City X to City Y

Question

Larissa and Steve each drove the same distance from City X to City Y in separate cars. Did it take longer for Larissa than for Steve to complete this trip?

(1) On this trip, Larissa’s average speed was 80 kilometers per hour and Steve’s average speed was 85 kilometers per hour.

(2) On this trip, Larissa and Steve each drove 68 kilometers.

ID 00926

OA is A, but can this question actually be answered? Nowhere is it mentioned that they kept a constant speed. Let's say the distance was 80 and Larissa kept a constant speed of 80kph. She would spend 1 hour driving, but if Steve spent the first 79 km driving 1 kph and then the remaining 1 km at 6799 kph, thus keeping his average speed at 85kph but he would clearly spend more time driving? If however, Steve also kept a constant speed of 85kph, he would definitely complete the distance in shorter time

GMATinsight · Answer

Hi erikvm,

In statement 1, it's mentioned that  On this trip, Larissa's average speed was 80 kilometers per hour and Steve's average speed was 85 kilometers per hour  which should be interpreted that whether they had constant speed or variable speed at every moment during their travel, finally they have been able to manage the average speeds of 80 and 85 Km/Hr.

Please Note: You may drive from your home to office at 10 Km/hr and office to home at 20 km/h at constant speed but the average speed of the entire journey will be 40/3 km/hr whereas you have never driven at 40/3 km/h at any point of time in your journey. So average speed is the reflection of Total Distance travelled and total time taken

Average Speed = Total Distance / Total Time

i.e. Total Time = Total Distance / Average Speed

i.e. If distance travelled by two riders are equal then Ratio of Time will be reciprocal of ratio of their respective Average Speeds

GMATinsight · Answer

The Highlighted example that you have quoted is INCORRECT

Here is the explanation of your example which renders the average speed of 1.013 and not 85 kmph

AkshdeepS · Answer

Given: Distance is equal for both Larissa and Steve from city X to City Y.

St 1: Average speed of Larissa = 80 kms per hr
 Average speed of Steve = 85 kms per hr

As the distance is same we can say that Time taken by Larissa is more than time taken by Steve to complete the trip.  Sufficient

St 2: Distance = 68 kms

We don't know the speed.  Insufficient

(A)

swapnils10 · Answer

From condition 1, speed is given and In question stem Distance is same. Hence Speed 1 > Speed 2. so statement 1 is sufficient.

Fish181 · Answer

So are we just supposed to assume that it took them the same amount of time to drive there? What if larissa stopped at burger king for an hour but steve didn't stop?

Bunuel · Answer

(1) states that "  On this trip  Larissa’s average speed was 80 kilometers per hour and Steve’s average speed was 85 kilometers per hour."   This means that their average speeds account for any stops or interruptions during the trip. Therefore, regardless of any potential stops, the average speed reflects their overall speed for the entire journey.

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Larissa and Steve each drove the same distance from City X to City Y

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Larissa and Steve each drove the same distance from City X to City Y

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