DRDO Multi tasking staff Model paper 2

Let the cost price be Rs. x/article (Rs.x per article)
Selling price = Rs. y/article (Rs.y per article)
According to the problem,
⇒ 23x = 20y
⇒ y = 1.15x
∴ Gain percent
⇒

1.15x−x

x

× 100% = 15%