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speed

by ketkoag » Wed Jun 10, 2009 9:28 am
A and B go home from their school. Does A arrive home earlier than B?
1) A's home is 30 miles far than B's
2) B is 10% slower than A
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Source: — Data Sufficiency |
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by tohellandback » Wed Jun 10, 2009 9:46 am
IMO E
1.not sufficient. speed is required
2. not sufficient-distance required

together..let's say B's home is X miles from school
A's home-X+30 miles
let's say speed of A is 10, B's speed is 9
time taken by A=(X+30)/10
time taken by B=X/9
to check which one is greater
subtract one from the other
X/9-(X+30)/10= (10X-9X-270)/90=(X-270)/90 you see this value is positive for X>270 and negative for X<270
so not sufficient
The powers of two are bloody impolite!!
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by ketkoag » Wed Jun 24, 2009 5:26 am
IMO E as well. wanna confirm the answer..
thanks..
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Re: speed

by kidcorpo » Thu Jun 25, 2009 9:45 am
ketkoag wrote:A and B go home from their school. Does A arrive home earlier than B?
1) A's home is 30 miles far than B's
2) B is 10% slower than A
Non-math required way to solve:

1) Insufficient alone. Speed not given.
2) Insufficient alone. Distance not given.

Combined: If B lives 0.1 miles away from school, and A lives 30.1 miles away from school, B will obviously get there first! We need to know how far at least one of the homes are, otherwise B could be anywhere from right beside the school (0 time to get home) to 1000 miles away from school!
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