Celyna bought 300 grams of candy A for \$ 5.00, and x grams of candy B for \$ 7.00. She calculated that the average price of all of the candy that she purchased was \$ 1.50 per 100 grams. What is the value of x?
Answer Choices
A. 525
B. 600
C. 500
D. 450
E. 900