Hello,
Can you please assist with this?
Thanks a lot,
Sri
OA: [spoiler]Miles Kerry is ahead: 8
Miles Jess finishes ahead: 3[/spoiler]
Jess is running her first ultramarathon (100 miles) with her
This topic has expert replies

 Legendary Member
 Posts: 641
 Joined: 14 Feb 2012
 Thanked: 11 times
 Followed by:8 members
GMAT/MBA Expert
 [email protected]
 Elite Legendary Member
 Posts: 10347
 Joined: 23 Jun 2013
 Location: Palo Alto, CA
 Thanked: 2867 times
 Followed by:508 members
 GMAT Score:800
Hi Sri,
This IR question is essentially about the Distance Formula (Distance = Rate x Time) and making sure that you take enough notes.
We're told that the race is 100 miles and that it's broken in HALVES (50 miles each). The question gives us the rates for both Jess and Kerri during the FIRST HALF of the race (5mph and 6mph, respectively) and during the SECOND HALF of the race (8mph and 6mph, respectively).
The first question asks HOW FAR ahead is Kerri when she reaches the halfway point. Since that is the "50 mile" measure, we can figure out how long it took Kerri to get to that point:
D = R x T
50mi = 6mph x T
50/6 = T
8 1/3 hrs = T
Now that we have the time, we can figure out how far Jess traveled in 8 1/3 hours...
D = (5mph) x (8 1/3 hours)
D = 41 2/3 miles
This means that when Kerri is at the 50 mile mark, Jess is at 41 2/3 miles. The difference is approximately 8 MILES
The second question asks how many miles Jess finishes ahead of Kerri. This means that at some point Jess PASSES Kerri and finishes the race first. So, let's calculate how long it took Jess to finish the race.
First part (50 miles at 5mph):
D = R x T
50mi = (5mph) x (T)
50/5 = T
10hrs = T
Second part (50 miles at 8mph):
D = R x T
50mi = (8mph) x (T)
50/8 = T
6 1/4hrs = T
Jess's total time = 10 + 6 1/4 = 16 1/4 hours to finish the race.
Since Kerri's speed was constant (6mph), we can figure out how far she went in 16 1/4 hours:
D = R x T
D = (6mph) x (16 1/4hrs)
D = 97 1/2 miles
So, Jess is approximately 3 MILES ahead of Kerri when Jess finishes the race.
GMAT assassins aren't born, they're made,
Rich
This IR question is essentially about the Distance Formula (Distance = Rate x Time) and making sure that you take enough notes.
We're told that the race is 100 miles and that it's broken in HALVES (50 miles each). The question gives us the rates for both Jess and Kerri during the FIRST HALF of the race (5mph and 6mph, respectively) and during the SECOND HALF of the race (8mph and 6mph, respectively).
The first question asks HOW FAR ahead is Kerri when she reaches the halfway point. Since that is the "50 mile" measure, we can figure out how long it took Kerri to get to that point:
D = R x T
50mi = 6mph x T
50/6 = T
8 1/3 hrs = T
Now that we have the time, we can figure out how far Jess traveled in 8 1/3 hours...
D = (5mph) x (8 1/3 hours)
D = 41 2/3 miles
This means that when Kerri is at the 50 mile mark, Jess is at 41 2/3 miles. The difference is approximately 8 MILES
The second question asks how many miles Jess finishes ahead of Kerri. This means that at some point Jess PASSES Kerri and finishes the race first. So, let's calculate how long it took Jess to finish the race.
First part (50 miles at 5mph):
D = R x T
50mi = (5mph) x (T)
50/5 = T
10hrs = T
Second part (50 miles at 8mph):
D = R x T
50mi = (8mph) x (T)
50/8 = T
6 1/4hrs = T
Jess's total time = 10 + 6 1/4 = 16 1/4 hours to finish the race.
Since Kerri's speed was constant (6mph), we can figure out how far she went in 16 1/4 hours:
D = R x T
D = (6mph) x (16 1/4hrs)
D = 97 1/2 miles
So, Jess is approximately 3 MILES ahead of Kerri when Jess finishes the race.
GMAT assassins aren't born, they're made,
Rich

 Newbie  Next Rank: 10 Posts
 Posts: 1
 Joined: 17 Feb 2015
We're told that the race is 100 miles and that it's broken in HALVES (50 miles each). The question gives us the rates for both Jess and Kerri during the FIRST HALF of the race (5mph and 6mph, respectively) and during the SECOND HALF of the race (8mph and 6mph, respectively). ???
_____________
GuL
_____________
GuL
GMAT/MBA Expert
 [email protected]
 Elite Legendary Member
 Posts: 10347
 Joined: 23 Jun 2013
 Location: Palo Alto, CA
 Thanked: 2867 times
 Followed by:508 members
 GMAT Score:800
Hi pyaramosam,
Do you have a question about this IR prompt?
GMAT assassins aren't born, they're made,
Rich
Do you have a question about this IR prompt?
GMAT assassins aren't born, they're made,
Rich