Question

A man can row his boat with the stream at 5 km per hour and against the stream at 31/2 km per hour. how much distance he can going his boat in a lake(still water) in 2 hours?

Answer 1

Step-by-step explanation:

Let Distance be =D

Speed in upstream=14−10=4 km/hr

Speed in downstream=14+10=24

Time =

S

D

According to question

4

D

+

24

D

=4

24

7D

=4⇒=

7

96

=13.71km

Answer 2

Answer:

8.5 km

Step-by-step explanation:

Formula used:

speed of boat in still water=1/2( downstream speed+ upstream speed)

=> downstream speed= 5 km/h

upstream speed = 7/2 km/h

using the formula mentioned above, we get

speed of boat in still water= 1/2( 5+7/2)

= 1/2 ( 17/2)

= 4.25 km/h

let distance traveled be x,

time given= 2 hours

=> 4.25= x/ 2 {speed=distance/time}

x => 8.5 km

ANSWER: 8.5 km