Correct Answer - Option 2 : 25%

**Given**

SP of 15 books - CP of 15 books = SP of 3 books

SP of 15 books - SP of 3 books = CP of 15 books

SP of 12 books = CP of 15 books

**Formula **

%Profit = [(SP – CP)/CP] × 100

**Calculation **

Let, CP of 1 book be X Rs.

Then CP of 12 books = 12X Rs.

And SP of 12 books = 15X

%Profit = [(15X – 12X)/12X] x100

⇒ (3/12) x 100

⇒ 25%

**∴ Profit% in the given transaction is 25%**