First you must calculate the time it takes for her to travel the 10m down vertically.
Once you know that time, that is also the time that she has to travel 5m horizontally.
So you can calculate her horizontal speed necessary by dividing the distance (5m) by the time.
SOLVED :)
Homework Statement
https://tycho-s.phys.washington.edu/cgi/courses/shell/common/showme.pl?courses/phys114/winter08/homework/04d/2blocks_incline_NWT/5.gif
The figure shows two identical blocks tied together with a string which passes over a pulley at the crest of the inclined...