Question

moving 40 km downstream and 36 km upstream a boat takes 10 hours . when it moves 30 km upstream and 30 km downstream it takes 8 hours . find the speed of boat and stream​.​

Answer 1

Step-by-step explanation:

let us assume that the boat steram in water is x

so x-8

40/x+8+36/x-8=10

30/x-8+30/x+8=8

A.C qyestion

40(1/x+8)+36(1/x-8)=10............eq1

30(1/x-8)+30(1/x+8)=8...............eq2

take 1/x-8=p,1/x+8=q

eq1 and eq2 by elimination method

3(40p+36q=10)

4(30p+30q=8)

=120p+108q=30

=120p+120q=32

= -12q=-2

q=12/2=6

substitue q value in eq 1