Giving a loan in a foreign currency
Q: I have some money in the form of foreign currency which I bought for investment purpose a year ago at 15.75/ unit of currency. Now one of my friends needs some money and he approached me to lend him some amount for a few months. As I don't have money in the form of Pakistaani Rupees, I told him to take foreign currency from me and get it exchanged with Pakistaani rupees. But I put one condition that I have bought that currency @ 15.75/unit and now the market rate of that currency is 13/unit. I gave him 3000 units of currency no matter at which rate he will sell those units in the market but he will have to return me the money @ 15.75 on which I originally bought that units. For example if now he sold that 3000 units @ 13 in market he will get Rs.39000 but he will have to return me the money @ 15.75 which becomes Rs.47250. Is getting that extra amount justified by Shariah? Is it a Halaal transaction to do?