Question

Cost of production of each unit of electricity is 3 less than twice the total number of units produced. If the total cost of production is 20, find the number of units of electricity produced?

Answer 1

Total cost of production = x(2x-3)

x(2x-3) = 20

2$x^2$ – 3x – 20 = 0

2$x^2$ - 8x + 5x – 20 = 0

2x(x-4) + 5(x-4) = 0

(2x+5)(x-4) = 0

x= -2.5 or x=4

As number of electricity units cannot be negative,

No. of electricity units produced = 4