Question

Quantity I: Vipin can swim at 6 km/hr in still water. The river flows at 3 km/hr and it takes 8 hours more upstream then downstream for the same distance. How far is the place? Quantity II: A man can row 25 km/hr in still water and the river is running at 15 km/hr. if the man takes 2 hr to row to a place and back, how far is the place?

Answer 1

Answer:

1) 36 kmph

2) 16 kmph

Step-by-step explanation:

Formula:

Upstream Speed = u - v

Downstream Speed = u + v

where u is speed of boat or swimmer in still water and v is rate of stream

Distance = Speed * time

Quantity 1

Given

u = 6 kmph

v = 3 kmph

Difference in taken for upstream and downstream travel = 8 hours

Solution

Let X be the distance traveled

Upstream Speed = 6-3 = 3 kmph

Downstream Speed = 6+3 = 9 kmph

Difference in taken for upstream and downstream travel = 8 hours

$\frac{x}{3} - \frac{x}{9} = 8$

$x = 36 \: km$

Distance = 36 km

Quantity 2

Given

u = 25 kmph

v = 15 kmph

Total time taken for upstream and downstream travel = 2 hours

Solution

Let X be the distance traveled

Upstream Speed = 25-15 = 10 kmph

Downstream Speed = 25+15 = 40 kmph

Total time taken for upstream and downstream travel = 2 hours

$\frac{x}{10} + \frac{x}{40} = 2$

$x = 16 \: km$

Distance = 16 km