Question

Ritu can row downstream 20 km in 2 hours, and upstream 4 km in 2 hours. Her speed of rowing in still water and the speed of the current is:


(a)6km/hr and 3km/hr
(b)7km/hr and 4km/hr
(c)6km/hr and 4km/hr
(d)10km/hr and 6km/hr​

Answer 1

Answer:

c is correct answer 6km/hr and 4km/hr

Answer 2

Answer:

Let speed of Ritu

in still water be x km/hr.

in current water be y km/hr

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)

By Adding eqn. (i) and eqn. (ii),

x + y = 10

x - y = 2

2x = 12

x = 6

Substituting the value, x = 6 in eqn. (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.

hence,

c is the correct option