Question 939624
Let the price of 1 banana be x
Selling price of 100 bananas is 100* x
Gain, i.e profit after selling is 20* x

To find percentage gain, we need Cost price
Cost price = Selling price- profit =100x-20x=80x

Therefore %Gain = Gain/CostPrice *100
= {{{(20/80) *100}}}
%Gain = 25%

QED