Question

only genius persons can solve this question

Answer 1

each book cost price = 100/12
and selling price = 150/12
gain= 50/12 on each book
gain % =( 50/12)/(100/12) ×100
=====》 50%

Answer 2

here is your answer


hope it helps you ☺️☺️☺️
please make the answer as brainlist