Final answer:
Joan's total displacement is 2 blocks East over 3 minutes, so her average velocity is 0.67 blocks/min East. This makes (c) 0.67 blocks/min East the correct answer.
Step-by-step explanation:
Joan's average velocity can be calculated by considering her total displacement divided by the time of travel. Since Joan walks four blocks East and then two blocks West, her total displacement is 4 blocks East - 2 blocks West = 2 blocks East. Given that this displacement occurs over a period of three minutes, we can calculate her average velocity as follows:
Total Displacement = 2 blocks East
Total Time = 3 minutes
Average Velocity = Total Displacement / Total Time = 2 blocks / 3 minutes = 0.67 blocks/min East
Therefore, the correct answer to the question is (c) 0.67 blocks/min East.