Question

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?

Answer 1

The average velocity of Sandy is given by the total distance covered S divided by the total time taken t:
$v= \frac{S}{t}$

The total distance covered is
$S=200 km+0+100 km=300 km$
while the total time taken is 2 hours + half an hour (for the rest) + 1 hour and half, so
$t=2h+0.5h+1.5 h=4 h$
Therefore, the average velocity is 
$v= \frac{S}{t}= \frac{300 km}{4 h}=75 km/h$