the current in a stream moves at a speed of 10 mph. a boat travels 17 mi upstream and 17 mi downstream in a total time of 10 hr. What is the speed of the boat in still water?

Answer 1

let speed of boat in still water be x mph

17/(x-10) + 17/(x+10) = 10
time (x-10)(x+10)

17(x+10) + 17(x-10) = 10(x^2 - 100)
34x = 10x^2-1000
10x^2 -34x - 1000 = 0
x = 11.84 or some negative speed

x = 11.84

Answer 2

42. A boat can be rowed 9 km. upstream or 18km. downstream in a period of 3 hrs. Whatis the speed of the boat in still water in km/hr? (A) 4 km/hr (B) 45 km/hr (C) 3 km/hr (D) 3-5 km/hr n