Question

in still water, the speed of the boat 10 mi/h. camilla drives the boat upstream for 60 min. and then downstream to her starting point in 20 min. what is the speed of the stream?

Answer 1

Answer:

5 mi/h

Step-by-step explanation:

S = v*t

S - space (miles)

v - velocity (mi/h)

t - time (h)

stream speed = x

The distance upstream(S_1) is expressed by :

60 min -> 1 hour

S_1 = (10-x)*1

The distance downstream is expressed by :

20 min -> 0.3(3) hour

S_2 = (10+x)*0.3(3)

The distance traveled upstream for 60 min is equal to the distance traveled downstream in 20 min. -> S_1 = S_2

(10-x) * 1 = (10+x)*0.3(3)

10 - x = 3.3(3) + 0.3(3)x

6.6(6) = 1.3(3)x

x = 6.6(6) / 1.3(3)

x = 5 mi/h