<h2>

</h2><h3>Let speed of Ritu </h3>
<h3> in still water be x km/hr.</h3><h3> in current water be y km/hr.</h3>
Speed of water while upstream is (x + y) km/hr,
downstream is (x – y) km/hr,
2(x + y) = 20 x + y = 10 ………… (i)
2(x – y) = 4 x – y = 2 …………… (ii)
<h2> By Adding eqn. (i) and eqn.</h2>
x + y = 10
x - y = 2
_______________
x = 12

(ii), Substituting the value,
<h3> x = 6 in eqn. </h3>
(i), x + y = 10 6 + y = 10 y = 10 – 6
∴ y = 4
∴ Speed of Ritu in still water, x = 6 km/hr. in current water, y = 4 km/hr.