Answer:
a) $7.27344
b) 263.974 hours
Step-by-step explanation:
a)
+) 1 day = 24 hours
+) The cost for 1000 watts each hour is $0.05051 so that each hour use of 1 watt costs: $0.05051 / 1000 = $0.00005051
+) Each hour, each electric heater uses 1200 watts costs: $0.00005051 x 1200 = $0.060612
=> In 24 hours, to heat each electricity heater costs: $0.060612 x 24 = $1.454688
=> In 24 hours, to heat 5 electricity heaters costs: $1.454688 x 5 = $7.27344
<em>So that it costs $7.27344 to heat her house for 1 day</em>
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b)
As calculated, the cost to use 1 watt in one hour is $0.00005051
=> The cost to use 75 watts in one hour is: $0.00005051 x 72 = $0.00378825
Assume that the hours of using 72 watts to cost $1 is x (hour)
So that: $0.00378825 * x = $1
=> x = 1/ 0.00378825= 263.974 hours
<em>It takes 263.974 hours for a 75-watt lightbulb to stay on to result in $1 electricity charges</em>
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