20 ml of a liquid with 5.4 x 10 9 organisms/ml. You need exactly 3 x 102 organisms/ml in at least 25 ml but you have only the following dilutions and pipets. You must use the dilutions as is (no removing or adding volumes) and you can only use the pipets once. The pipets are only calibrated to the volume specified i.e. they are not graduated.
Supplies:
Pipets Dilutions Blanks
1 - .1ml 1 - 99.9ml 2 - 12ml
1 - 10ml 3 - 8ml 1 - 3ml
5 - 1ml 3 - 6ml 1 - 2ml
1 - 2ml 3 - 4ml
1 - 3ml 1 - 71ml
1 - 4ml 1 - 65ml
1 - 5ml 1 - 24ml