Alex and Brenda both stand at point X. Alex begins to walk away from Brenda in a straight line at a rate of 8 miles per hour. One hour later, Brenda begins to ride a bicycle in a straight line in the opposite direction at a rate of R miles per hour. If R > 8, which of the following represents the amount of time, in terms of R, that Alex will have been walking when Brenda has covered twice as much distance as Alex?	Options:
A) R-4
B) R/(R+4)
C) R/(R-16)
D) 8/(R-8)
E) 2R - 4
Let T be the time thatAlexwill have been walking when Brenda has covered twice as much distance as Alex.   In T hours Alex will cover 4T miles;   Since Brenda begins her journey 1 hour later than Alex then total time for her will be T-1 hours, and the distance covered in that time will be R(T-1);   We want the distance covered by Brenda to be twice as much as that of Alex: 2*8T=R(T-1) --&gt; 16T=RT-R --&gt; T=R/(R-16).   Answer: R/(R-16).
<result>C</result>
Alex and Brenda both stand at point X. Alex begins to walk away from Brenda in a straight line at a rate of 8 miles per hour. One hour later, Brenda begins to ride a bicycle in a straight line in the opposite direction at a rate of R miles per hour. If R > 8, which of the following represents the amount of time, in terms of R, that Alex will have been walking when Brenda has covered twice as much distance as Alex?