Ann, running at a constant pace, ran part of a marathon in 2 hours.

Question

Ann, running at a constant pace, ran part of a marathon in 2 hours. Elisabeth, running at a constant pace, completed the remainder of the marathon in 3 hours. If Ann had continued running at her constant pace and completed the marathon, what would her finishing time have been?
(A marathon is 26.2 miles.)

(1) Elisabeth ran 3 times as far as Ann did.

(2) Elisabeth ran twice as fast as Ann did.

Bunuel · Accepted Answer

GMATNinja Video Solution:

https://www.youtube.com/watch?v=bGI8xQhpEsY

ankushsambare · Answer

We need to know Ann's finishing time if she ran the entire marathon.
Let Ann's speed = A and Elisabeth's speed = E.
Ann ran for 2 hours, so her distance = 2A.
Elisabeth ran for 3 hours, so her distance = 3E.
Total marathon distance = 26.2 miles.
Statement (1):
Elisabeth ran 3 times as far as Ann.
So:
3E = 3(2A)
3E = 6A
E = 2A
Total distance:
2A + 3E = 26.2
2A + 6A = 26.2
8A = 26.2
A is determined.
Therefore Ann's full-marathon time = 26.2/A is determined.
 Sufficient. 
Statement (2):
Elisabeth ran twice as fast as Ann.
E = 2A
Total distance:
2A + 3(2A) = 26.2
8A = 26.2
A is determined.
Therefore Ann's full-marathon time is determined.
 Sufficient. 
Each statement alone is sufficient.
Answer:  D .

Tinytrotter · Answer

As per me the little information about the distance of the marathon = 26.2 miles is irrelevant and is often confusing.

Simply told, we know Ann ran part of the marathon in 2 hours, Elisabeth completed the remainder in 3 hours.

Statement 1: Elisabeth ran 3 times as far as Ann did.

Which means that Ann would take 6 hours (3*2) to run the same distance Elisabeth did with her own speed. Therefore, her total finishing time would be 6+2 = 8 hours. Hence sufficient

Statement 2: Elisabeth ran twice as fast as Ann did

Which means whatever distance Elisabeth covered in 3 hours (which is the remainder of the marathon), Ann would have taken 6 hours (3*2) to run the same distance. Add that to her original 2 hours and her final run time becomes 8 hours.

Hence sufficient.

Therefore, Option (D) is correct.

Ann, running at a constant pace, ran part of a marathon in 2 hours.

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 Data Sufficiency (DS) Questions

Ann, running at a constant pace, ran part of a marathon in 2 hours.

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