a river flows at 2km/hr and sarah takes 6 hrs to row 16km up the river and 16km back.how fast did she row?
Distance D = Rate R * Time T
R = rate she rowed
R + 2 = combined rate (rowing and river current)
RT = D
(R + 2)*6 = 16
6R + 12 = 16
6R = 4
R = 4/6 = 2/3 = 0.67
R = 0.67 km/hr rowing
To find out how fast Sarah rowed, we need to calculate her average rowing speed, which can be determined by dividing the total distance she rowed by the total time taken.
First, let's determine the total distance Sarah rowed. Since she rowed 16 km up the river and then 16 km back, her total distance is 16 km + 16 km = 32 km.
Next, let's calculate the total time taken by Sarah. Given that the river flows at 2 km/hr and she took 6 hours to row both ways, her rowing time against the current is 6 hours, and her rowing time with the current is also 6 hours. Therefore, her total rowing time is 6 hours + 6 hours = 12 hours.
Finally, we can find Sarah's average rowing speed by dividing the total distance she rowed (32 km) by the total time taken (12 hours):
Average rowing speed = Total distance / Total time
= 32 km / 12 hrs
= 2.67 km/hr
Therefore, Sarah's average rowing speed is 2.67 km/hr or approximately 2.7 km/hr.