Solving this problem Algebratically

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1

<p>Hi guys,</p>

<p>I want to know how do you solve this problem algebratically.</p>

<p>Toni bicycles to work at a rate of 20 miles per hour, then takes the bus home along the same route at a rate of 40 miles per hour. What is her average speed for entire trip?</p>

<p>D = VT;</p>

<p>lets say D = n;</p>

<p>then, n/20 = T1; N/40 = T2; We need Average speed = TotalDistance/TotalTime</p>

<p>I solved it like this I got a common denomitor 40 * 20 its not the least one,but I was lazy to compute the prime factors 20 * 40 = 800;</p>

<p>then T1 = 800/20 = 40 hours; T2 = 800/40 = 20;</p>

<p>N1 + N2 = TotalDistance = 1600;
T1 + T2 = TotalTime = 60;</p>

<p>1600/60 = 80/3;</p>

<p>Two days ago I had problems with rate problems,but now they are easy I just need to know how to solve this algebraically.</p>

<p>Thanks in advance.</p>

2

<p>for a problem like this, you’ll hear this from almost every CC user</p>

<p>2<em>rate1</em>rate2 / ( rate1+rate 2)</p>

<p>Xiggi’s formula for problems like this</p>

<h2>(2(20)(40))</h2>

<p>(20 + 40)</p>

<h2>1600</h2>

<p>60</p>

<p>which is about 27 mph</p>

3

<p>^thanks alot for this formula.</p>