Answer:100 units
Step-by-step explanation:
Let Original sale = x unit
And
Given :his sales reduced by 20 units , So
New sale = x - 20
And
As given : If the square of new sale reduced by 400 gives 60 times the original sale. So we get
( x - 20 )2 - 400 = 60x
( x2 + 400 - 40x ) - 400 = 60x
x2 + 400 - 40x - 400 = 60x
x2 - 40x = 60x
x2 = 100x
x = 100
So,
Original sale = 100 unit