Calculate blood flow???

I've been given a past paper for biology but I have no clue how to calculate the answer as we have not covered the topic yet.

The rate of blood flow in a capillary is 0.2 mm s-1, calculate the time it would take for blood in the capillary to flow from point A to B
There is a diagram showing part of the Alveolus and a capillary with 10 um being the key.

Im sure the calculation is simple but until you have been shown how to calculate the answer it will remain a mystery.

Any help would be greatly appreciated