10^6 positrons are flowing normally through an area in forward direction and same amount of electrons are flowing in backward direction in the interval of 10ms. Find the current through that area

Hello Rishika, as electrons flow in opposite to that positrons then conventional positive charges flow in the same direction as that of positrons. Hence total number of charges is 2 * 10^6.
Each charge = 1.6 * 10^-19 C
Total charge = 2 * 10^6 * 1.6 * 10^-19 C
Time taken = 10 m s = 10 * 10^-3 s
Current = charge / time = 3.2 * 10^-13 / 10 * 10^-3 = 3.2 * 10^-11 A