How many liters of a 0.80%\% (m/v{\rm m/v}) NaCl{\rm NaCl} solution can be prepared from 500mLmL of a 9.0%\% (m/v{\rm m/v}) stock solution?

Answer 1

L1 x %1 = L2 x %2
?L x 0.8% = 0.5L x 9%
?L = ?