One small island community in the pacific currently uses 2 megawatts (MW) of electricity per year. All this electricity is generated from coal

Question

One small island community in the pacific currently uses 2 megawatts (MW) of electricity per year. All this electricity is generated from coal. The community plans to add x MW of windmill generation capacity to its system to meet increasing demand. How many megawatts of windmill generation capacity must be built in order that 20% of the communities total electricity usage comes from windmills? 

Answer 1

Since x is the increase in MW, the total number of MW would be (x + 2).

 

Also, the MW from windmill is 20% of total usage => x/(x + 2) = .2

 

Solving for x: x = .2(x + 2) = .2x + .4

                     .8x = .4

                     x = 0.5 MW