Sandy is on a road trip. she leaves at 8: 00 am. it takes her 2 hours to drive 200 kilometers. she stops at a rest stop for half an hour. then, she drives for 100 more kilometers, which takes her an hour and a half. what is sandy's average velocity?

The average velocity of Sandy is given by the total distance covered S divided by the total time taken t:


The total distance covered is

while the total time taken is 2 hours + half an hour (for the rest) + 1 hour and half, so

Therefore, the average velocity is 

The boat's velocity relative to the riverbank can be resolved into two components. the component going north is 2.7 m/s and the component going west is 1.2 m/s.we add these two vectors and then find the magnitude of the resultant to get the speed.the magnitude of the resultant vector from adding can be obtained by the pythagorean theorem.    to two significant figures, the boat's speed relative to the riverbank is 3.0 m/s.