Some articles were bought at 6 articles for Rs. 5 and sold at 5 articles for Rs. 6. Gain percent is ?

Suppose, number of articles bought = L.C.M. of 6 and 5 = 30

Cost Price (C.P) of 30 articles = Rs.( 5 / 6 ) x 30
= Rs. 25

Selling Price (S.P) of 30 articles = Rs.( 6 / 5 ) x 30
= Rs. 36

Gain % = ( 11 / 25 ) x 100%
= 44%