Respuesta :

Let the cost of 7 pencils be 'x' & the cost of 10 pencils be (7x + 15)/10

According to the Question,

⇒(7x + 15)/10 = x

⇒7x + 15 = x × 10

⇒7x + 15 = 10x

⇒7x - 10x = 15

⇒3x = 15

⇒x = 15/3

⇒x = 5

∴ The cost of a pencil is ₹5