For Samantha, 2 tick marks east is 120 units east because 1 tick is 60 units.
For Ryu, 8 tick marks west is 480 units west because 1 tick is 60 units.
They are walking to form a line. Just add their distances from 0.
120 + 480 = 600.
--------------------------0----------------------------
Ryu: 480 Samantha: 120
480 + 120 = 600.
600 units, or feet.