Find the speed of the boat in still water and the speed of the current.

Question

Solve by two linear equations using elimination or substitution.

 

It took a patrol boat 5 h to travel 60 km up a river against the current, and 3 h for the return trip with the current. Find the speed of the boat in still water and the speed of the current.

Answer 1

d=r*t

60=(r-c)(5)

60=(r+c)(3)

simplify both equations

12=r-c

20=r+c

add

32=2r

r=16 kph (speed of the boat)

c=4 kph  (speed of the current)