20 10/9/ 1 sold 4 futures at 1.8690.

20 10/9/ 1 bought 250,000 pounds at 1.8654.

Future profit and loss = (1.8690-1.8425) * 62500 * 4 = 6625.

Spot profit and loss = (1.8420-1.8654) * 250,000 =-5850.

Final profit and loss = 6625-5850 = 775

Contract Quantity = 250,000/62,500 = 4