Answer:
28%
Explanation:
Hello,
When the item is reduced by 10%, this is like we multiply this price by 1-0.10=0.90
When the item is reduced by 20%, this is like we multiply this price by 1-0.20=0.80
When the item is reduced by 10% and then by 20%, this is like we multiply this price by 0.90*0.80=0.72
so this is equivalent that the item is reduced by 28% (as 1-0.28=0.72)
hope this helps