Question

A Boat is rowed upstream 40 kilometre and downstream 45km in 13 hours it is also rowed upstream30 km and downstream 27 km in 9 hours find the speed of the boat and that of stream

Answer 1

Step-by-step explanation:

speed upstream = x

speed downstream = y

time = distance/time

Time upstream + time down stream = 13 hours

40/x +45/y = 13

let 1/x =a and 1/y =b

40a+45b =13................(1)

Similarly

30/x +27/y 9

30a+27b=9..................(2)

40 a + 45 b = 13 .............1

Total value

30 a + 27 b = 9 .............2

Eliminate y

multiply (1)by -3

Multiply (2) by 5

-120 a -135 b = -39

150 a + 135 b = 45

Add the two equations

30 a = 6

/ 30

a = 1/ 5

plug value of a in (1)

40 a + 45 b = 13

8 + 45 b = 13

45 b = 13 -8

45 b = 5

b = 1/ 9

a= 1/ 5

therefore x=5 speed upstream

b= 1/ 9

y=9 speed downstream

so speed of boat = 7 km/h

speed of current = 2 km/h

Answer 2

$\huge\blue{refer\:to\: attachment!!...}$

hope!!...it helps uhh...❣️

Mark it as brainliest...✌️