Math
posted by alice .
The amount of a monthly electric bill (B, measured in $) depends
on the amount of electricity used that month (E, measured in
kWh). A typical public utility charges $0.12 per kWh for the first
300 kWh used, $0.17 per kWh for the next 600 kWh used, and
$0.29 per kWh for any excess electricity used that month.
How much would I have to pay if the amount of electricity used was 800? I'm a bit confused about how to calculate this...

300 + 500 = 800
.12(300) +.17(500) = ?