An electric iron of 500 W power is used daily for 30 minutes. If the cost per kW.h is $0.10, what is the weekly expense in using the electric iron??

weeklyexpense= power*time*costkwhr where power is in kw, time in hrs,

weekly expense= .5*7*.5*.10

check that.

To find the weekly expense in using the electric iron, we need to calculate the total energy consumed by the electric iron in kilowatt-hours (kWh) and then multiply it by the cost per kWh.

First, let's calculate the energy consumed by the electric iron in kilowatt-hours (kWh):

Power (in kW) = 500 W / 1000 = 0.5 kW (since 1 kW = 1000 W)

Time (in hours) = 30 minutes / 60 = 0.5 hours (since there are 60 minutes in an hour)

Energy (in kWh) = Power × Time = 0.5 kW × 0.5 hours = 0.25 kWh

Now, we can calculate the weekly expense:

Weekly expense = Energy consumed (in kWh) × Cost per kWh

Given that the cost per kWh is $0.10, we have:

Weekly expense = 0.25 kWh × $0.10/kWh

Finally, calculating the weekly expense:

Weekly expense = 0.25 kWh × $0.10/kWh = $0.025

Therefore, the weekly expense in using the electric iron is $0.025 or $0.03 (rounded to two decimal places).