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
Answers
Answered by
1
Answer:
c is correct answer 6km/hr and 4km/hr
Answered by
1
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
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