<p>Edna and Nacy leave the house of a common friend at the same time and walk for 4 hours. Edna walkes due east at the average rate of 4 kilometers per hour and Nancy walks due eat at the average rate of 3 kilmoters per house. What is the straightline distance between them at the end of the 4 hours?</p>
<p>A) 4
B) 5
C) 12
D) 16
E) 20</p>
<p>THIS IS NUMBER 7 ON PAGE 532</p>
<p>Well if Edna walks 4 kilometers per hour then in 4 hours she would have walked 16 kilometers. Nancy walks at 3 kilometers per hour which would mean she walks 12 kilometers in 4 hours. The distance between them after four hours is clearly: </p>
<p>A) 4.</p>
<p>Number 14 on page 534.... im stumped... again</p>
<p>this one has a diagram</p>
<p>markpterson slightly expanded on the 532/7 question, telling us that Nancy is so hungry she eats 3 kilmoters at each house. :D
Meanwhile, according to the BB, she is also moving due north 3 km/hr.
Connect the dots (on the map): Edna's and Nancy's final positions and the departure point. It's a 3-4-5 right triangle blown up 4 times.
5x4 = 20. (E).</p>
<p>534/14.
KN // LM, x = NLM.</p>
<p>NLM = 180 - LNM - LMN.
LMN = 180 - 125 = 55.
LNM = LMN since the triangle NLM is isosceles.
NLM = 180 - (2) 55 = 70.
x = 70.</p>
<p>I dont understand.. u lost me at NLM=180-LNM-LMN</p>
<p>x is angle KNL.</p>
<p>1.
angle KNL = angle NLM since KN // LM.</p>
<p>2.
From the triangle NLM
angle NLM = 180 deg - angle LNM - angle LMN <<------- eq.1.</p>
<p>3.
LNM and LMN are equal angles at the base of the isosceles triangle NLM (LN=LM),
angle LNM = angle LMN <<------- eq.2.</p>
<p>4.
angle LMN is supplementary to the 125 deg angle:
angle LMN = 180 deg - 125 deg = 55 deg.</p>
<p>5.
Plugging 55 deg into eq.1 for both LNM and LMN (because of eq.2)
angle NLM = 180 - 55 - 55 = 70 deg.</p>
<p>x = 70.</p>
<hr>
<p>As is often the case on SAT math questions,
there is a shorter solution - finding x from the angle KNM;
there is also a longer solution - finding x from the triangle KNL;
there is even a longer one - finding x from the triangle JNL.
You may want to work them out as an exercise.
I hope our answers will be the same. :)</p>
<hr>
<p>This may serve as another argument in favor of being tutored:
learning, among other things, how to find the shortest way to the correct answer.
Sorry for tooting my old horn, but I blow it very rarely. :D</p>