Q7

This topic has expert replies
Source: — Problem Solving |

Legendary Member
Posts: 829
Joined: Mon Jul 07, 2008 10:09 pm
Location: INDIA
Thanked: 84 times
Followed by:3 members

Re: Q7

by sudhir3127 » Wed Nov 26, 2008 10:34 pm
bacali wrote:OA: E
plugging in is the best approach

let the distance be 100
and x percentis 50%
thus,

first half time = 5/4
second half will be = 5/6

average speed = total distance/total time

100/( 5/4+ 5/6) = 1200/25

which is E.

hope that helps..

Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Thu Nov 27, 2008 3:17 pm
Similar approach

Take x distance as 40 since the first speed is 40 miles/hr to find the time i.e 40/40=1hr

Take remaining distance as 60 speed = 60/60=1 hr

Avg speed = total distance travelled/total time taken
= 100/2 = 50 miles/hr

Only E will work (i.e give 50 miles/hr as the answer) if u plug in 40 for x

User avatar
Legendary Member
Posts: 2134
Joined: Mon Oct 20, 2008 11:26 pm
Thanked: 237 times
Followed by:25 members
GMAT Score:730

by logitech » Thu Nov 27, 2008 4:22 pm
if x = 0 %

it means that that the average speed is 60!

and when x = 100% the V = 40

Extremes are your friends. Hangout with them!

Hence, E
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"

Legendary Member
Posts: 708
Joined: Sun Jun 01, 2008 4:59 am
Location: USA
Thanked: 13 times
Followed by:1 members

by niraj_a » Thu Nov 27, 2008 4:34 pm
logitech and PC are quant gods!