Answer both questions please?

2) A stock solution of a dye is labelled with a concentration of M/5000. Three 250cm3 conical flasks (A, B, and C) were set up. The following amounts of dye solution were added to each flask: (A) 25cm3 (B) 50cm3 and (C) 100cm3. a) What is the concentration of dye in the stock solution? (2 marks) b) Water is added to each flask, bringing the total volume of the flask up to 250cm3. What is the concentration now of the dye in each flask