Graphing calculator

Question

A motorboat travels 175 kilometers in 5 hours going upstream. It travels 275 kilometers going downstream in the same amount of time What is the rate of the boat in still water and what is the rate of the current?

Answer 1

175 up, 275 down, 45 km/hr in still water. current = 10 km/hr

distance = rate of speed times time traveled

d=rt =5r t=5 hours

175 = 5(r-c)

275 =5(r+c) where r= boat speed in still water and c = current speed.

add the two equations

450 = 10r

r = 450/10 = 45 km/hr = boat speed in still water

5c = 275 -5r = 275 -5(45) = 275- 225 = 50

c = 50/5 = 10 km/hr = current speed

55 x 5= 275 km

35x5 = 175 km

upstream: 225-50 = 175 km/5 hrs

downstream" 225+50 = 275 km/5 hrs