Question

A man sold 20 articles for Rs.60 and gained 20%. How many articles did he buy for Rs.60?

Answer 1

Let buying price=BP
Selling price Rs60= buying price for 20 articles+ gain
 we are told gain is 20% which means gain=(BP)X (20/100) = 0.2 BP
that shows selling price =60= BP + 0.2BP Which means 60=1.2 BP
from which we gets BP= Rs50. 
He got 20 articles for Rs 50  or (20/50)  article per  each Rs.
 So for Rs60 he will get (2/5) X 60    which is  24