Answer :
prices changed from 100% price to 80% price due to sale.
100% - 20% = 80%
THEN increased by 25% so
80% + 25% = 105%
so the overall effect is that the price rose from the original (100%) to 105%
so a 5% increase
100% - 20% = 80%
THEN increased by 25% so
80% + 25% = 105%
so the overall effect is that the price rose from the original (100%) to 105%
so a 5% increase