According to the records of an electric company serving the certain

town area, the mean electricity consumption for all households during winter is

1650 kilowatt-hours per month. Assume that the monthly electricity consumptions

during winter by all households in this area have a normal distribution with a mean

of 1650 kilowatt-hours and a standard deviation of 320 kilowatt-hours. The

company sent a notice to John informing him that about 90% of the households

use less electricity per month than he does. What is John's monthly electricity

consumption?