BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

test32 #13

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 269
Joined: Sun Apr 01, 2007 5:41 am

test32 #13

by dunkin77 » Tue Apr 24, 2007 5:46 pm
13. Carl drove from his home to the beach at an average speed of 80 kilometers per hour and returned home by the same route at an average speed of 70 kilometers per hour. If the trip home took hour longer than the trip to the beach, how many kilometers did Carl drive each way?
(A) 350
(B) 345
(C) 320
(D) 280
(E) 240


Hi,
The answer is D) but I could not figure out.... can you help?
Top
Source: — Problem Solving |
User avatar
Legendary Member
Posts: 519
Joined: Sat Jan 27, 2007 7:56 am
Location: India
Thanked: 31 times

by Neo2000 » Tue Apr 24, 2007 6:41 pm
A difference of speed caused a difference of One? hour For which of the options does this match up? That will be your answer.

Which leads me to think that maybe the Question is worded wrongly.
Top
Master | Next Rank: 500 Posts
Posts: 269
Joined: Sun Apr 01, 2007 5:41 am

by dunkin77 » Tue Apr 24, 2007 7:22 pm
Neo, thanks so much for your help.

Sorry, I think one word bolded was missing from the text...

13. Carl drove from his home to the beach at an average speed of 80 kilometers per hour and returned home by the same route at an average speed of 70 kilometers per hour. If the trip home took 1/2 hour longer than the trip to the beach, how many kilometers did Carl drive each way?
Top
User avatar
Legendary Member
Posts: 519
Joined: Sat Jan 27, 2007 7:56 am
Location: India
Thanked: 31 times

by Neo2000 » Tue Apr 24, 2007 7:28 pm
All right, since we know its 30mins, look for the answer options that are multiples of 70 and 80 and then divide with 70 and 80 and see which one of them will give you a difference of 30mins.

In this case, only 280 since 280/70 = 4hrs and 280/80 = 3.5hours hence 280kms
Top
User avatar
Community Manager
Posts: 789
Joined: Sun Jan 28, 2007 3:51 pm
Location: Silicon valley, California
Thanked: 30 times
Followed by:1 members

Re: test32 #13

by jayhawk2001 » Tue Apr 24, 2007 9:25 pm
Just posting an alternative for the equation inclined...

From the question, we know that time taken for (trip-home = trip-beach + 1)

Let x be the distance between home and beach.

x/80 + 1/2 = x/70
(x + 40)*70 = 80x
x = 280
Top
Legendary Member
Posts: 559
Joined: Tue Mar 27, 2007 1:29 am
Thanked: 5 times
Followed by:2 members

by Cybermusings » Wed Apr 25, 2007 4:37 am
13. Carl drove from his home to the beach at an average speed of 80 kilometers per hour and returned home by the same route at an average speed of 70 kilometers per hour. If the trip home took 1/2 hour longer than the trip to the beach, how many kilometers did Carl drive each way?
(A) 350
(B) 345
(C) 320
(D) 280
(E) 240

Time = D/S
Let distance be x
x/70 - x/80 = 1/2
10x=5600/2
10x = 2800
x=280
Hence D
Top
Post new topic Post Reply
• Page 1 of 1