Edgar borrowed a total of $10,000 from three sources: the bank, his mom, and a close friend. after one year, he paid a total of $624 in simple interest toward the three loans. the bank charged an interest rate of 7% per year, his mom charged 5%, and the friend charged 6%. the amount he borrowed from his mom exceeded the amount he borrowed from his friend by $200. what amount did edgar borrow from the bank?