Aspen has 306306306 green beads and 210210210 silver beads. For every 5\,\text{cm}5cm5, start text, c, m, end text of a belt that Aspen sews, they use 404040 green beads and 242424 silver beads.
After how many centimeters of the belt will Aspen have equal numbers of green and silver beads left?