Question

The speed of the current in a river is 2 km/hr. If a boat is rowed downstream for
a distance of 34.5 km in 3hrs, find the speed of the boat in still water.

Answer 1

Answer:

an example

Step-by-step explanation:

since the equation of lines which been intersected is given as;

2 x+3 y=21⟶(1)

and 3 x−4 y+11=0

⇒3 x−4 y=−11⟶(2)

(1)×4+(2)×3

8x+12y=84

9 x−12y=−33

17x+0=51

x=3⇒4 y=20⇒ Y=5

∴ x=3 and Y=5

coordinate of point of intersection is (3,5)

since the distance of point (3,5) from the line 8x+6 y+5=0 is given as

d=

A

2

+B

2

∣Ax

1

+By

1

+C∣

=

8

2

+6

2

∣8⋅3+6⋅5+5∣

=

10

59