an electric heater draws 1100 W of power. Electricity costs eight cents per kW•h. How much does it cost to operate the heater 3h a day for 30 days?

Me because some of question i don’t understand

Suppose you are choosing a 6-digit personal access code. this code is made up of 4 digits chosen from 1 to 9, followed by 2 letters chosen from a to z. any of these digits or letters can be repeated. find the total number of personal access codes that can be formed. 492,804 341,172 39,917,124 4,435,236

Type the correct answer in the box. use numerals instead of words. if necessary, use / for the fraction bar. a city water tank holds 20 gallons of water. a technician empties 25% of the tank. how many more gallons of water must be removed from thetank so that it has 5 of the water that it started with: the technician must removemore gallons of water for the tank to have 5 of the water that it started with.