here's the solution.........!!!!
-2/5 multiply by the denominator of 1/2 then u will get=-4/10
1/2 multiply by the denominator of -2/5 then u will get=5/10
now the denominator's are same,but we don't have ten rational no. between these two numbers.
now the question is to find 10 rational number then multiply -4/10 & 5/10 by 5 u will get -20/50 & 25/50.
so, the required rational numbers are:- -19/50, -18/50, -17/50, -16/50, -15/50, -14/50, -13/50, -12/50, -11/50, -10/50...............and a lot more.
thanks.........