Ritu can row downstream 20 km in 2 hour, and upstream 4 km in 2 hours. Find her speed of rowing in still water and the speed of the current
Answers
6 kmph is the speed at which Ritu rows 4 kmph is the speed of the current.
Given:
Ritu downstream is 20 km in 2 hours.
Ritu upstream is 4 km in 2 hours.
To find:
Speed of rowing in still water =?
Speed of the current =?
Solution:
The speed of the rowing on still water denoted by M kmph.
The speed of the stream denoted by N kmph.
The upstream speed of Ritu’s rowing is (M – N) kmph
The downstream speed of Ritu’s rowing is (M + N) kmph
2(M+N)=20 _______________________ (1)
2(M-N)=4 ________________________ (2)
Solving the equation, we get
2(M+N)=20;
2(M-N)=4;
M-N=2;
M=2+N;
Substituting M=2+N in equation (1)
2(M+N)=20
2(2+N+N)=20 ;
N=4
Substituting N = 4 in equation (1),
2(M+N)=20
2(M+4)=20
2M+8=20
2M=20-8
2M=12
M=6
the value of M = 6.
Therefore, the speed at which Ritu rows is 6 kmph and the speed of the current is 4 kmph.
Answer:
Step-by-step explanation:
Given :-
Ritu can row downstream 20 km in 2 hour, and upstream 4 km in 2 hours.
Solution :-
Let the speed of Ritu in still water and the speed of stream be x km/h and y km/h.
Upstream = (x – y) km/h
Downstream = (x + y) km/h
According to the question,
⇒ 2(x + y) = 20
⇒ x + y = 10 ... (i)
⇒ 2(x – y) = 4
⇒ x – y = 2 ... (ii)
Putting this equation in (i), we get
⇒ y = 4
Ritu’s speed in still water is 6 km/h
The speed of the current is 4 km/h.