Riya purchases some pen @ 6 pen for ₹5 and he sells all the pen @ 5 p…

             Price    :    Qty

Buy :        5      :      6             ......(i)

Sell :        6      :      5             ......(ii)

(i) × 5 & (ii) × 6, to make the equal quantity.

             Price    :     Qty

Buy :      25      :      30

Sell :      36       :      30

Here,

C.P. of 30 articles = Rs.25

S.P. of 30 articles = Rs.36

Profit = 36 - 25 = Rs.11

Hence,

Profit percent = \(\frac{11}{25}\) × 100% = 44%