Assume today settlement price on a CME EUR futures contract is $13140/EUR. you have a short position in a contract. Ypur performance bond account currently has a balance of $1700. The next three days settlement prices are $13126, $13133, and $13049. Calculate the chages in the performance bond account from daily marking to market and the balance of the performance bond account after the third day. My question is which formula is used in this question and how?