A 890 mL NaCl solution is diluted to a volume of 1.15 and a concentration of 8.00 . What was the initial concentration?

How do I go about this?

M1V1=M2V2? and if it is how do I replace the variables?

1 answer

Probably M1V1 = M2V2 BUT you give no units. 1.15 what. concn of 8.00 what.
You call 890 V1 and M1 is what you want.
V2 is 1.15 whatever and 8.00 is M2 whatever. Since V1 is 890 mL you need V2 in mL. Whatever unit the 8.00 is will be that unit in M1.