Question 564187
your calculations for the 100 and 1000 are fine; you need to repeat the same technique from those on the 10 calculation


increasing the number of kwh lowers the average cost because the fixed cost portion of the bill ($7.50) is spread out over more kwh


the electric company charges $.09/kwh, so the average cost can never go below that value
___ the average will get closer to $.09 as the number of kwh increases and the fixed costs are spread of more kwh


$.12 = ($7.50 + $.09x) / x ___ .12x = 7.5 + .09x ___ .03x = 7.5 ___ x = 250