Let assume he had x toys and bought it for Rs.y per piece.

Now, we can form these two equations from these

x*y = 900;//Total cost

(y+2)(x-5) = 900+80; //as he mad profit of Rs.80 by selling x-5 toys in Rs.(y+2).

On solving the above two equation we will get x=75 and y=12

**Number of toys = 75**

Initial Cost = 12