You have a test tube which contains a 10 ml suspension of white blood cells, at a concentration of 1.25 x 10⁶ cells/ml.

You need a 5 ml suspension at a concentration of 5 x 10⁴ cells.

What volume of the original suspension will you need to make this sample? (Provide your answers in μl, but you don't need to include units in your answer.)