You have 2 different savings accounts. For Account​ A, the simple interest earned after 3 months is ​$1.75. For Account​ B, the simple interest earned after 21 months is ​$17.50. If the interest rate is 3.5​% for Account A and ​2.5% for Account​ B, how much is the principal in each​ account? Which account earned you the most interest the first​ month? Explain your answer.