Question

Revie A boat takes 3.4 hours to travel 45 km down a river, then 7.0 hours to return. Part A Determine the speed of the water in the river. Express your answer in kilometers per hour. IVO AQ R o 2 ? V = km/h

Answer 1

Anscoca! - speed at starting = speed of boat + Speed of riva = 3.4 hours for 45km = 13.24 km/h speed at reton = Speed of boat speed of river = this for 45km = 6.43 km/h let x be speed of beat and y be the speed of rivee x+y = 13.24 2-4 = 6.43 2x = 19.67 =) X= 9.8 km so, y = 3.44 kmine speed of wate in rivee = 3.44 emins

Answer 2

SOLUTION :

Let speed of water in the river be w km/hr and speed of boat be b km/hr

So, 

time taken to travel 10 km down the river = 45 / (b + w)

=> 3.4 = 45 / (b + w)

=> b + w = 45 / 3.4 = 13.24 km/hr ………… (1)

time taken to travel back 10 km up the river = 45 / (b - w)

=> 7 = 45 / (b - w)

=> b - w = 45 / 7  = 6.43 km/hr ………… (2)

Add (1) and (2) :

=> 2 b =19.67 km/hr

=> b = 9.84 km/hr

=> w = 13.24 - 9.84  = 3.40 km/hr (ANSWER).