Harriet ran a 1000 \mathrm{~m} course in 380 seconds. She ran the first 720 \mathrm{~m} of the course at a constant speed of 3 \mathrm{~m} / \mathrm{s}. She ran the remaining part of the course at a constant speed of v \mathrm{~m} / \mathrm{s}. What is the value of v ?
Answer Choices
A. 2
B. 1.5
C. 3
D. 1
E. 4.5