Simple differential equation modelling question.

Question

The question is: A chemical dissolves in water at a rate equal to 10% of the amount of undissolved chemical per hour. At time $t$ hours the amount of undissolved chemicalis $x$ grams. Initially the amount of undissolved chemicalis $6$ grams. Find the differential equation $$\frac{dx}{dt}.$$ Now I am pretty sure it is either $$\frac{dx}{dt}=\frac{6-x}{10} $$ or $$\frac{dx}{dt}=6-\frac{x}{10}$$ but I am unsure which one.