In rail transport, track gauge is the spacing of the rails on a railway track and is measured between the inner faces of the load-bearing rails.
Most of the modern train are based on broad gauge. The separation in broad gauge is about 5 ft and 6 inches and in the standard gauge the separation between the tracks is 4 ft and inches. So for the modern train it is not possible to travel on the tracks whose separation is no more than 4.5 feet.
Get them to have a common denominator. 100 is the common denominator, so change 7/10 and 3/5 to have a denominator of 100. 7/10=70/100 and 3/5=60/100. So from least to greatest it will go 8/100, 3/5, 7/10.