Question

4)You count your cells and have 8x10ᶺ5 viable cells/ml you want to see (dilute the cells) to end up with 2x10ᶺ5 viable cells/ml. What volume of cells will you put into 20 ml?

Answer 1

you are diluted them 4 times. So, one part original concentration,three parts solvent.

4 parts in 20 ml
1 part (5ml) original
3 parts (15ml) solvent.