If Ancial's salary is currently 80,000 francs per month and it increases by 20%, you would calculate the increase by multiplying her current salary by 20% and then adding that increase to her current salary.
20% of 80,000 francs is:
(20/100) * 80,000 = 16,000 francs
So, the increase in salary is 16,000 francs.
Adding this increase to her current salary:
80,000 francs + 16,000 francs = 96,000 francs
So, Ancial's salary after a 20% increase would be 96,000 francs per month.