72.0 ml of a 1.50 M solution is diluted to a volume of 288 mL. A 144 mL portion of that solution is diluted using 185 mL of water. What is the final concentration?

moles in 72 mL =

0.072 L x 1.50 M = ?? moles
M = ??moles/0.288 L = xxM

moles in 144 mL =
0.144 x xxM = zz moles
M = zzmoles/L soln.