5. An Australian company sells yen futures contracts to cover possible exchange losses on its export orders denominated in Japanese yen. The amount of the initial margin is AUS\$50,000, and the maintenance margin is 75% of the initial margin. The value of the company's position declines by AUS $15,000 because the spot rate for yen has increased. a) Calculate the maintenance margin? b) Should the broker issue margin calls to the company? And by how much