Question 787784
<font face="Times New Roman" size="+2">


Let *[tex \Large r] represent Lisa's rate and then *[tex \Large r\ +\ 10] must represent John's rate.


Then there are two ways to look at this.  If it took 5 hours for both of them to cover *[tex \Large 600] miles, then the sum of their speeds must have been *[tex \Large 600\ \div\ 5\ =\ 120\ \text{mph}].  So then *[tex \Large r\ +\ (r\ +\ 10)\ =\ 120].  Solve for *[tex \Large r]


Or you can say that the sum of their speeds is *[tex \Large r\ +\ r\ +\ 10\ =\ 2r\ +\ 10] and then that *[tex \Large \frac{600}{2r\,+\,10}\ = 5].  Again, solve for r.


You can check your work by doing it both ways.  If you get two different answers, you have at least one arithmetic mistake.


For the second part of the question, Lisa traveled *[tex \Large 5r] miles and John traveled *[tex \Large 5(r\,+\,10)] miles, which is to say 50 miles farther than Lisa.


John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
<font face="Math1" size="+2">Egw to Beta kai to Sigma</font>
My calculator said it, I believe it, that settles it
<div style="text-align:center"><a href="http://outcampaign.org/" target="_blank"><img src="http://cdn.cloudfiles.mosso.com/c116811/scarlet_A.png" border="0" alt="The Out Campaign: Scarlet Letter of Atheism" width="143" height="122" /></a></div>
</font>