Question 23094
Higher wattage means that it takes LESS time to consume the electricity.  If the 60 watt bulb takes 2.5 times as long to use electricity, then the 150 watt bulb will use the same electricity in 1/2.5 times as long.  If it takes 16.6 hours for a 60 watt bulb to use 1kWh, then the 150 watt bulb will take {{{16.6/2.5= 6.64 }}} hours.


Check:  
60 watts * 16.4 hours = 996 watt-hours
150 watts * 6.64 hours = 996 watt-hours


No Extra Charge:  Notice the answer in the check is 996 watt-hours, which is almost 1000 watt-hours.  Now, what is the word for 1000?  Isn't it "kilo"?  In other words "kilo-watt-hours"!!  Get it???  And why is it 996 watt-hours, which is APPROXIMATELY 1000 watt-hours, instead of EXACTLY 1000 watt-hours or one kilo-watt hour?  Answer:  Because in the problem it says that "It takes a 60-watt bulb ABOUT 16.6  hours to use 1kWh of electricity," which is rounded off!  If you used (60 watts)*(16.6666666. . . hours), it would come out EXACTLY 1 kilowatt hour!!


R^2 at SCC