No(0)Let the cost price of the 20 pens be ₹100.
Cost of each pen=₹100/20=₹5
Selling price of each 25 pens sold=₹100/25=₹4.
%LOSS:
If cost of each pen. = 5=100%
..selling price of each pen. = 4= ?%.
Cross multiply:5? =400
?=80%
So,%loss= 100%-80%=20%
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