Two siblings, sibling A and sibling B, are saving money for their summer vacation. The amount of money that sibling A has in their savings account, y, can be represented by the equation y = 10x + 25, where x represents the number of weeks. Sibling B's savings can be represented by the equation y = 5x + 50. Based on the graph of this system of linear equations, after how many weeks will their savings accounts have the same amount of money?
A. 2.5 weeks
B. 5 weeks
C. 15 weeks
D. 75 weeks