After buying a toy from the shop, I am left with ₹ 15 from my 100 rupees of pocket money. Then the cost of toy (in rupees) is:
85
Let, the cost of the toy be x as it is the unknown.
Now,
⇒x+15=100
⇒x=100−15
⇒x=85
Thus, the cost of toy is ₹ 85.