Hey there!
I'm going to set up the equation slightly different.

2/100 or 1/50 :p la respuesta
Answer:
I think its 2 kg anyone correct me if I'm wrong!
Yesterday's price of notebook = $3.45
Today's price of notebook = $3.20
We have to determine the percentage decrease in the cost of notebook.
Percentage decrease = (Decrease
Old price) 
So, percentage decrease = 
=
= 7.246%
= 7.25%
Therefore, there is 7.25% of decrease in the cost of the notebook.