Question

A man Swim 6KM/H in
still water.if
the speed of the current is 4 km/h how
long will he take to Swim15 km


(1) Up Stream (2) Downstream​

Answer 1

Answer:

up stream 7hours 30 min and down stream 1 hour 30 min

Answer 2

(1). Up Stream -the time  taken by man  to swim 15 km  will be 7.5 hours.

(2). Downstream - the time  taken by man  to swim 15 km will be 1.5 hours.

Step-by-step explanation:

Given:

The swim speed  of the man in still water is 6 km/h.

The speed of the current is 4 km/h.

The  man swim  distance is 15 km.

To Find:

(1). Up Stream -the time  taken by man  to swim 15 km .

(2). Downstream - the time  taken by man  to swim 15 km .

Formula Use:

Upstream  speed of  the man  = (p−q) km/hr, where  p is the speed of the man in still water and q is the speed of the current           ---------formula no.01

Downstream speed of  the man  = (p+q)Km/hr, where  p is the speed of the man  in still water and  q is the speed of the current.       ----- formula no.02

Solution:

Considering - (1).Upstream.

As given- The man swim speed in still water is 6 km/h.

p=6 km/hr

As given - The speed of the current is 4 km/h

q= 4 km/hr

Applying formula no. 01.

Upstream  speed of  man $=p-q$

                                            $= 6-4$

                                            = 2 km/hr

As given - The  man swim  distance is 15 km.

The time taken by the man to swim 15 km = Swim  distance/ Upstream  speed of the  man

                                                                       $=\frac{15}{2}$ =

                                                                        = 7.5 hours

   Thus, Upstream -the time taken by the man to swim 15 km  will be  7.5 hours.                              

Considering - (2). Downstream

As given- The man swim speed in still water is 6 km/h.

                 p=6 km/hr

As given - The speed of the current is 4 km/h

                  q= 4 km/hr

Applying formula no. 02.

Downstream  speed of  the man $=p+q$

                                                       $=6+4$

                                                       = 10 km/hr

As given - The  man swim  distance is 15 km.

The time taken by man to swim 15 km = Swim  distance/ Downstream  speed of  the man

                                                                $=\frac{15}{10}$

                                                               = 1.5 hour

   Thus, Downstream- the time taken by the man to swim 15 km  will be 1.5 hour.