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Distance and Time from OG

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Distance and Time from OG

by safisana » Sat Sep 27, 2008 8:21 pm
This question is from powerPrep pracrice test

One hour after Yolanda started walking from X to Y, a distance of 45 miles, Bob started walking along the same road from Y to X. If Yolandas waling rate was 3mile per hour and Bob's was 4 miles per hour, how many miles had Bop walked when they met?

a. 24
b.23
c.22
d.21
e.19.5

Just wondering if there is a shorter way out.

This is how understood

since Yolanda started one hour ahead, she had covered 3 miles already
D= S * T 3m/h * 1 hr = 3
therefore remaining distance is 45-3=42
Sice they are moving in the opposite direction, add their speed
3+4 = 7m/h
therefore, time = 42/7 = 6hrs

hence bob would travel 4*6 = 24 miles

Please let me know if there is a shortcut

Safisana
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by vr4indian » Mon Sep 29, 2008 6:24 am
there is not shorcut method for this kind of example

but its very easy.. it will hardly take 30-45 second once you understand question

Thanks
Vishal Shah
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by vanesslondon » Tue Sep 30, 2008 7:22 am
Because 'meeting' SDT qs confuse me, I've decided to do them the non-algebraic way (since it is hit and miss for me) so i would just calculate how far they got in 1 hr, 2hrs, 3 hrs etc. Even the MGMAT online class which uses this question presents this simple method as a plausible alternative to algebra. Just something to bear in mind if yo find these hard!
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Re: Distance and Time from OG

by dally_gmat » Fri Oct 03, 2008 11:36 am
Total distance = 45

Let they meet aftr t hours
so Yolanda travelled for t hrs and Bob for (t-1) hours

Eq:

3t + 4(t-1) = 45

=> t = 7
Bob travelled 4 (7-1) = 24

safisana wrote:This question is from powerPrep pracrice test

One hour after Yolanda started walking from X to Y, a distance of 45 miles, Bob started walking along the same road from Y to X. If Yolandas waling rate was 3mile per hour and Bob's was 4 miles per hour, how many miles had Bop walked when they met?

a. 24
b.23
c.22
d.21
e.19.5

Just wondering if there is a shorter way out.

This is how understood

since Yolanda started one hour ahead, she had covered 3 miles already
D= S * T 3m/h * 1 hr = 3
therefore remaining distance is 45-3=42
Sice they are moving in the opposite direction, add their speed
3+4 = 7m/h
therefore, time = 42/7 = 6hrs

hence bob would travel 4*6 = 24 miles

Please let me know if there is a shortcut

Safisana
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