A boat is moving with a speed of 5 m/s and crosses the river in 10 minutes.what is the width of the river? [Hint: Distance travelled by the boat is width of the river.]
Answers
Step-by-step explanation:
Let the velocity of the river be x km/hr.
Given that,
Speed of the boat = 5 km/h
Width of the river (AB) = 1 km/h
Time taken to cross the river by boat = 15 minutes
The covered distance by the boat,
D=vt
D=5×6015
D=1.25km/h
Now, AB=1km/h
AC=1.25km/h
And angle B=900
Now, apply Pythagoras theorem ΔABC
(AB)2+(BC)2=(AC)2
(1)2+(BC)2=(1.25)2
(BC)2=(1.25)2−(1)2
BC=0.75kM
The covered distance by the river water in 15minutes is 0.75km.
Now, the velocity of the river
v=tD
v=410.75
v=3km/h
Hence, the velocity of the river water is 3 km h−1.
Answer:
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Step-by-step explanation:
ANSWER
Let the velocity of the river be x km/hr.
Given that,
Speed of the boat = 5 km/h
Width of the river (AB) = 1 km/h
Time taken to cross the river by boat = 15 minutes
The covered distance by the boat,
D=vt
D=5×
60
15
D=1.25km/h
Now, AB=1km/h
AC=1.25km/h
And angle B=90
0
Now, apply Pythagoras theorem ΔABC
(AB)
2
+(BC)
2
=(AC)
2
(1)
2
+(BC)
2
=(1.25)
2
(BC)
2
=
(1.25)
2
−(1)
2
BC=0.75kM
The covered distance by the river water in 15minutes is 0.75km.
Now, the velocity of the river
v=
t
D
v=
4
1
0.75
v=3km/h
Hence, the velocity of the river water is 3 km h
−1
.
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