#(3" miles")/(30" minutes")=(6" miles")/(60" minutes")=(6" miles")/("hour")#
#36 " miles" xx ("hour")/(6" miles")#
#color(white)("XXX")=color(red)(cancel(color(black)((36)))color(white)("X")^6) color(blue)(cancel(color(black)(" miles") ))xx"hour"/(color(red)(cancel(color(black)(6)) color(blue)(cancel(color(black)(" miles")))))#
#color(white)("XXX")=6 " hours"#